HYDRAULIC    AND    PLACER 
MINING  ISrlS 


BY 


EUGENE    B.   WILSON 


THIRD  EDITION,    THOROUGHLY  REVISED 
TOTAL  ISSUE   FIVE   THOUSAND 


NEW   YORK 

JOHN   WILEY   &    SONS,  INC. 

LONDON  :  CHAPMAN  &  HALL,  LIMITED 

1918 


w 


Copyright,  1898,  1907,  1918 

BY 
EUGENE  B.  WILSON 


Stanhope  ipress 

F.    H.  GILSON  COMPANY 
BOSTON,  U.S.A. 


PREFACE  TO   THIRD   EDITION 


THE  first  edition  of  "  Hydraulic  and  Placer  Mining  "  was 
written  to  meet  a  demand  for  an  elementary  treatise  on  the 
subject. 

Ten  years  later  the  book  was  revised,  and  now,  another  ten 
years  having  elapsed,  a  third  edition  is  published  with  addi- 
tional information  that  further  widens  its  scope  and  it  is 
hoped  its  usefulness. 

Naturally  new  ideas'  have  advanced  the  first  principles, 
and  we  find  the  Giant  has  expanded  from  its  original  field, 
that  of  disintegrating  gold-bearing  gravel  beds,  to  dislodging 
different  kinds  of  minerals  and  materials  from  their  resting 
places. 

The  use  of  streams  of  water  in  stripping  or  washing  away 
the  cover  from  different  mineral  deposits  goes  to  show  that 
the  conservation  of  energy  applies  to  brains  as  well  as  all 
things  else. 

Within  the  past  ten  years  veritable  mountains  of  wasted 
coal  that  covered  the  landscape  in  the  vicinity  of  anthracite 
mines  in  northeastern  Pennsylvania  have  disappeared, 
washed  away  by  streams  of  water  issuing  from  nozzles. 
Much  of  this  coal  has  been  reclaimed,  while  the  remainder  has 
gone  into  the  mines  to  help  fill  the  ever-increasing  excavations. 

The  possible  uses  of  streams  of  water  in  mining  operations 
are  on  the  increase ;  in  fact  where  natural  pressure  is  unavail- 
able artificial  pressure  developed  by  the  aid  of  high-speed 
centrifugal  pumps  is  brought  into  use. 

iii 


382J69 


iv  PREFACE 

The  writer  wishes  to  express  his  obligations  to  President 
H.  C.  Parmelee  of  the  Colorado  School  of  Mines  and  to 
Professor  L.  C.  Hills  for  permitting  the  use  of  the  article  on 
Graphical  Hydraulics;  also  to  John  Powers  Hutchins  who  so 
critically  read  the  second  edition  that  he  assisted  in  clearing 
up  typographical  errors. 

Kindly  criticism  is  always  appreciated  by  an  author,  be- 
cause he  is  sure  of  the  other  kind,  which  however  is  of  ten- 
tunes  helpful. 

Many  practical  men  have  requested  by  letter  that  some  of 
the  text  in  the  second  edition  be  explained.  Whenever  such 
letters  show  that  the  writer  is  striving  to  increase  his  knowl- 
edge and  hence  usefulness  the  author  takes  pleasure  in  an- 
swering them. 

E.  B.  WILSON. 

SCRANTON,  PA. 


PREFACE   TO    SECOND    EDITION. 


THE  demand  for  the  first  edition  of  this  work,  and  the  great 
activity  developed  in  placer  mining,  due  in  a  large  measure 
to  the  great  returns  from  this  species  of  work,  as  well  as  the 
very  substantial  profit  accruing  to  the  exploitation  of  the 
placers,  has  led  the  author  to  present  this  second  edition. 

There  have  also  been  many  new  methods  for  catching  the 
free  gold,  as  well  as  great  improvements  in  the  machinery 
for  handling  the  material,  and  in  the  application  of  new 
machinery  to  placers  where  unusual  difficulties  were  encoun- 
tered in  working  them. 

All  these  considerations  have  led  the  author  to  issue  the 
new  edition,  which  in  his  opinion,  brings  this  work  abreast 
of  the  latest  improvements  in  this  industry.  He  desires  to 
acknowledge  his  indebtedness  to  the  various  technical  jour- 
nals, as  well  as  to  the  engineers  whose  names  appear  in  the 
text. 

The  manner  in  which  this  subject  is  presented,  the  author 
thinks,  will  appeal  not  only  to  those  engaged  in  placer  min- 
ing, but  to  those  who  desire  to  get  the  latest  ideas  relating 
to  this  industry. 

THE  AUTHOR. 


CONTENTS. 


CHAPTER  I. 

GEOLOGY  OF  PLACER  DEPOSITS,  PLACER  PROSPECTING,  PLACER 
TESTING,  PLACER  VALUING i 

CHAPTER  II. 
HYDRAULIC  MINING,  SALT  MINING,  BOOMING,  CULM  MINING    .      50 

CHAPTER  III. 

DEVELOPMENT  OF  PLACER  MINING:  PAN,  ROCKER,  SLUICING,  LONG 
TOM,  SLUICE  BOXES,  TRANSPORTING  POWER  OF  WATER,  FLOW 
OF  WATER  IN  SLUICE  BOXES,  TRANSPORTING  POWER  OF  WATER, 
FLOW  OF  WATER  IN  SLUICE  BOXES,  GRADE  ........  61 

CHAPTER  IV. 
RIFFLES,  UNDERCURRENTS,  HUNGARIAN  RIFFLES,  DUMP  ....     136 

CHAPTER  V. 
WATER  SUPPLY,  MINER'S  INCH,  WEIRS,  FLUMES 152 

CHAPTER  VI. 

PIPE  LINES,  FLOW  OF  WATER  THROUGH  PIPES,  STRENGTH  OF  PIPES, 
PIPE  BENDS,  WATER  GATES,  AIR  VALVES,  PRESSURE  Box, 
DITCH  LINES,  FLOW  OF  WATER  IN  DITCHES,  SIPHONS  ...  174 

CHAPTER  VII. 
GIANTS  AND  HYDRAULIC  ELEVATORS 210 

CHAPTER  VIII. 

PLACER  MINING  INVESTMENTS,  COST  OF  HYDRAULICKING,  THE 
CLEAN-UP,  RETORTING  THE  MERCURY,  DRIFT  MINING,  BLAST- 
ING GRAVEL  BANKS,  MINING  IN  ALASKA 227 

vii 


Vlll  CONTENTS 

PAGE 

CHAPTER  IX. 

MINING  IN  NORTH  CAROLINA,  LOG  WASHER,  STEAM  SHOVEL  MIN- 
ING, CABLEWAY  MINING 249 

CHAPTER  X. 
DREDGING,  DESCRIPTION  or  DREDGES 264 

CHAPTER  XI. 

TRACTION    DREDGES,   DRY   PLACER   MINING    MACHINES,    DRY 
WASHERS     297 

CHAPTER  XII. 
BLACK  SANDS 3J4 

CHAPTER  XIII. 
UNITED  STATES  MINE  LAWS 333 

CHAPTER  XIV. 
CANADIAN  YUKON  LAWS 348 

CHAPTER  XV. 
INFORMATION  IN  HYDRAULICS 36& 


HYDRAULIC  AND  PLACER  MINING 


CHAPTER   I. 

GEOLOGY   OF   PLACER   DEPOSITS. 

THE  term  placer  is  defined  as  a  place  where  surface 
depositions  are  washed  for  the  valuable  minerals,  gold, 
tin,  tungsten  gems,  etc.  Placer  mining  is  defined  as 
washing  surface  depositions  for  gold. 

The  gold  found  in  alluvial  deposits  is  in  the  metallic 
state,  and  in  all  probability  was  derived  from  the  dis- 
integration of  gold-bearing  rocks  and  veins.  The 
chemical  and  mechanical  processes  that  freed  the  gold 
from  the  rocks  with  which  it  was  associated  are  numerous 
and  sometimes  obscure,  although  it  is  obvious  that  the 
elements  in  combination  with  water  and  ice  have  been 
the  chief  factors  in  tearing  rocks  apart  and  concen- 
trating the  gold. 

Most  placers  are  composed  of  quartz  pebbles,  sand, 
rocks  of  various  descriptions  and  sizes,  and  clay.  The 
gold  forms  a  very  small  portion  of  the  mass,  while 
quartz  sand,  with  garnets  and  black  sand,  the  latter 
composed  of  magnetite,  ilmenite,  and  hornblende,  make 
up  another  portion  of  the  mass. 

The  disintegration  of  rocks  is  occurring  continually, 
and  has  been  for  ages.  The  lighter  particles  are  carried 
away  by  wind  and  water,  and  the  heavier  are  left.  While 


2  GEOLOGY  OF  FLACER  DEPOSITS 

the  so-called  elements  -  y/ind,  heat,  cold  and  water  — 
have  been  the  chief  causes  of  disintegration,  there  are 
indications  that  glaciers  have  played  an  important  part 
in  the  erosion  of  rocks,  a^  they  moved  from  higher  to 
lower  levels,  particularly  in  the  more  northern  latitudes. 
Water  has  been  the  chief  factor  in  the  formation  and 
concentration  of  placers,  although  the  other  elements 
have  assisted. 

The  San  Juan  River  extends  from  North  Bloomfield 
to  Nevada  City,  California.  This  was  an  ancient  and 
by  some  called  a  tertiary  river,  that  cut  a  natural  chan- 
nel through  the  bed  rock.  In  time  the  channel  became 
partially  filled  with  wash  dirt  and  gravel  that  contained 
gold,  until  the  deposits  reached  a  thickness  of  500  feet. 
When  the  upheaval  occurred  that  formed  the  Sierra 
Mountains  the  river  bed  was  raised  high  above  its  origi- 
nal position.  Lava  flows  later  followed  the  upheaval, 
filled  the  ancient  river  channel,  and  covered  the  placer 
in  the  river  bottom  to  a  depth  of  from  200  to  400 
feet.  As  the  width  of  this  river  varies  from  one  to 
one  and  a  half  miles,  it  must  have  been  an  important 
water  course  in  its  time.  The  present  river  follows 
the  course  of  the  ancient  river;  however,  as  this  is  but 
one  of  many  ancient  rivers  it  is  reasonable  to  expect 
that  some  of  the  modern  rivers  would  cut  through  the 
lava  capping  of  the  old  placers  to  bed  rock  and 
form  modern  placers.  This  is  the  case,  so  that  two 
kinds  of  mining  are  needed  to  extract  the  gold  from  the 
two  differently  situated  ancient  placers.  Where  the 
ancient  river  beds  have  been  eroded  by  modern  rivers 
cutting  across  the  overlying  capping  of  lava,  secondary 


ANCIENT    SEA-BEACHES  3 

placers  have  been  formed  which  also  are  a  source  of 
gold. 

The  composition  of  the  gravels  in  these  ancient  river 
channels  represents  nearly  every  rock  in  the  vicinity, 
such  as  diabase,  diorite,  serpentine,  slate,  granite, 
syenite,  and  quartz.  The  lowest  gravels  in  some  placers 
have  a  blue  tint,  and  are  termed  the  "blue  lead"  since 
in  this  locality  the  richest  ground  is  found  above  bed- 
rock. The  depth  of  the  "pay  streak"  or  rich  gravel, 
is  from  2  to  6  feet  and  is  said  to  carry  from  $2.50  to 
$13.00  per  cubic  yard. 

From  data  furnished  by  writers,  it  would  appear  as 
if  ice  rivers  were  the  factors  that  disintegrated  and 
transported  the  gold  to  those  places  where  it  is  now 
found  in  Siberia  and  the  Klondike. 

Between  Cape  Nome  and  Point  Rodney,  Alaska,  for 
a  distance  of  25  miles,  there  is  an  ancient  sea-beach 
that  extends  back  from  the  ocean  a  distance  of  2500 
feet.  It  contains  a  placer  deposit,  with  the  pay  streak 
20  feet  above  sea  level,  and  from  12  to  32  feet  below  the 
surface.  From  the  westerly  base  of  Cape  Nome,  gravel 
terraces  or  ancient  beaches  rise  gently  to  the  north  and 
west,  forming  ridges  that  extend  4  or  5  miles  inland, 
until  their  highest  elevation,  250  feet,  is  attained.  Be- 
tween the  ridges  there  are  broad  valleys  that  contain 
tundra  or  arctic  swamps. 

Within  the  last  ten  years  the  tundra  have  been  pros- 
pected and  found  to  contain  very  rich  placer  ground. 
The  pay  streak  is  situated  just  above  bed  rock  at  depths 
varying  from  60  to  130  feet.  The  ground  is  as  a  rule 
frozen  to  bed  rock,  but  here  and  there  soft  places  are 


4  GEOLOGY  OF  PLACER  DEPOSITS 

encountered,  due  to  some  underground  circulation  of 
salt  water. 

The  bed  rock  is  sedimentary,  and  contains  gold,  ruby 
and  black  sands  that  have  been  cemented  in  mud  by 
quartz  solutions. 

Above  the  bed  rock  is  ruby,  magnetite  and  quartz 
sand  in  fairly  evenly  sized  grains,  with  some  quartz 
pebbles  and  gold  in  flakes.  This  is  the  pay  streak,  and 
above  it  to  the  surface  are  alternate  layers  of  rounded 
beach  gravel  and  gray  sands. 

The  pay  streak  is  so  marvelously  rich  in  the  tundra 
mines  of  Little  Creek  on  the  Seward  Peninsula,  it  is 
difficult  to  account  for  its  .origin.  One  theory  is  that 
glacial  rivers  formed  the  placers  by  pushing  ahead  of 
them  the  gold  and  gravel  they  ground  from  the  rocks 
they  passed  over.  Another  theory  is  that  the  receding 
waters  of  the  Arctic  Ocean  and  possibly  subsequent 
upheavals  produced  the  placers  and  the  beaches.  The 
third  theory  is  that  the  ocean  waves  pounded  the  coast 
rocks  to  pieces  and  concentrated  the  gold. 

In  the  eastern  United  States  along  the  coast,  glacial 
action  so  denuded  the  rocks  that  no  placers  are  reported 
north  of  Maryland.  From  Maryland  to  Georgia,  to 
the  east  of  the  Appalachian  Mountains,  placers  are 
found.  In  several  localities  in  Virginia  gold  is  found 
in  clayey,  sandy  soil,  containing  also  quartz  pebbles. 
The  gold  vein  is  not  far  from  such  deposits.  In  North 
Carolina,  the  gold  is  found  in  decomposed  Cambrian 
schists ;  and  in  chemically  altered  rocks.  In  such  places 
the  rock  contained  quartz  stringers  that  carried  the  gold. 
In  some  of  the  brooks  that  have  worn  away  these  deposits 


MOTHER  LODES  5 

free  gold  is  found,  but  the  placer  itself  has  not  been 
disturbed  by  either  glacial  or  water  erosion. 

In  the  early  days  it  was  assumed  that  all  placers  if 
traced  up  would  lead  to  the  discovery  of  their  source 
or  the  "  mother  lode,"  and  that  the  lode  would  prove 
infinitely  richer  than  the  placers.  The  lode  may  fre- 
quently be  found,  but  nine  times  out  of  ten  it  does  not 
contain  free  gold  in  anything  like  the  proportion  or  the 
size  of  grains  that  the  placers  would  indicate.  Original 
rocks  are  found  that  will  not  show  gold  to  the  naked 
eye,  and  at  times  not  with  a  magnifying  glass,  yet  the 
placers  from  these  rocks  contain  both  fine  and  coarse 
gold. 

The  Edith  mine  in  Catawba  County,  North  Carolina, 
is  an  instance  where  gold  is  found  in  nuggets  through 
the  disintegrated  rocks,  there  being  no  vein  present. 
The  Sawyer  mine  in  Randolph  County,  North  Carolina, 
and  the  M  orris ville  mine  in  Virginia  are  instances  where 
the  gold  is  so  fine  it  cannot  be  seen  with  the  eye,  •  yet 
both  have  placers  that  show  coarse  as  well  as  fine  gold. 
The  Breckenridge,  Colorado,  placers,  have  produced 
considerable  wire  gold,  and  the  mother  lode  is  traced 
with  reasonable  certainty;  yet  the  vein  has  never  paid 
when  worked. 

The  gold  ore  that  took  the  prize  at  the  Centennial 
came  from  Louisa  County,  Virginia,  yet  the  placers  in 
that  vicinity,  or  those  near  the  Cabin  John  mine,  Mary- 
land, do  not  show  such  large  nuggets.  From  what  has 
been  said  it  is  difficult  to  tell  from  the  size  of  placer 
nuggets  just  what  kind  of  gold  will  be  found  in  the 
mother  lode.  Gold  was  discovered  in  California  Gulch, 


6  GEOLOGY  OF  PLACER  DEPOSITS 

Colorado,  as  placer,  but  when  traced  to  Leadville  at 
the  head  of  the  Gulch,  the  greater  part  of  the  valuable 
deposits  were  silver-lead. 

The  richer  placers  of  California  did  not  lead  to  im- 
portant quartz  lodes,  and  the  Comstock  lode,  although 
rich  in  silver  and  gold,  did  not  show  gold  in  the  vein. 

The  history  of  placer  mining  is  such  that  to  trace  up 
a  placer  and  find  a  rich  free  milling-ledge  is  not  the 
rule,  but  generally  the  exception.  Rich  veins  have 
been  discovered  where  no  traces  of  placer  could  be 
found,  except  in  the  grass  roots  directly  over  the  vein, 
and  again  placers  have  been  found  where  no  vein  existed. 
That  gold  should  be  found  in  paying  quantities  and  in 
sizes  from  flour  to  nuggets  in  placers  and  not  in  the 
mother  lode  in  similar  sizes,  seems  mysterious,  and,  if 
some  placer  miners  are  to  be  believed  "it  grows."  This 
latter  statement  miners  will  illustrate  as  follows:  In 
1875  California  Gulch  was  washed  and  $20,000,000  in 
gold  was  recovered;  when  it  was  abandoned  one  could 
not  make  wages.  Of  course,  some  seeds  were  left, 
and  in  1885  it  was  washed  again  and  $5,000,000  recov- 
ered, the  inference  being  that  it  grew.  The  explana- 
tion that  possibly  millions  of  tons  of  gold-bearing 
material  were  concentrated  in  that  gulch  by  Nature, 
and  that  the  second  washing  was  only  the  leavings  of 
the  first,  will  not  satisfy  the  miner,  who  will  probably 
paraphrase  Job  and  reply,  "There  are  veins  of  silver; 
but  the  place  for  gold  is  where  you  find  it." 

Assume  that  two  small  pieces  of  gold  are  in  contact 
and  resting  on  a  rock,  and  again  assume  that  water 
moves  a  fair-sized  stone  so  that  it  strikes  the  gold  and 


AREA  OF   PLACERS  7 

welds  the  two  pieces.  This  assumption  is  not  unten- 
able if  one  will  consider  how  easily  the  dentist  welds 
gold  when  filling  a  tooth,  and  it  may  account  for  "gold 
growing." 

Water  has  in  some  instances  carried  the  gold  many 
miles  down  a  sloping  hard  river  bed,  and  eventually 
deposited  it;  in  other  instances  the  distance  traveled 
has  been  short. 

Gold  may  move  slowly  down  the  sides  of  a  mountain 
and  be  found  in  streaks  parallel  to  the  mountains  trend. 

Placer  deposits  are  found  in  narrow  streaks  or  in 
wide  belts,  according  to  their  location,  the  manner  in 
which  they  were  formed,  and  afterwards  acted  upon  by 
Nature's  forces. 

Gulch  placers  are  necessarily  narrow,  old  river  beds 
are  much  wider,  and  in  some  cases  where  there  have 
been  upheavals  and  severe  dynamic  disturbances  fol- 
lowed by  torrents  of  water  they  are  quite  wide.  The 
original  placer  may  have  been  spread  broadcast  over 
an  ancient  sea  or  lake  bottom  that  was  afterwards 
raised  by  an  upheaval  and  formed  what  is  now  known 
as  a  "dry  placer,"  that  is,  a  placer  in  a  locality  where 
there  is  no  water. 

Dry  placer  areas  are  quite  extensive,  and  are  found 
in  deserts  and  in  some  of  the  arid  counties  of  New 
Mexico,  Arizona,  Nevada,  Lower  California,  Mexico, 
Australia,  and  possibly  India.  Gold  is  not  equally  dis- 
tributed through  a  placer,  owing  to  the  current  shifting 
when  the  placer  was  formed,  for  which  reason  one  miner 
may  be  working  in  pay  dirt  while  another  a  few  feet 
away  is  not  making  wages.  The  miner  of  experience 


8  GEOLOGY  OF  PLACER  DEPOSITS 

is  very  cautious  in  following  up  his  pay  streak,  and  will 
dig  to  the  right  and  left  of  a  rich  spot  before  going  ahead. 

Gulch  mining  is  particularly  uncertain,  and  frequently 
the  richest  dirt  is  along  the  sides,  and  not  in  the  center 
of  the  gulch. 

No  one  can  with  absolute  satisfaction  explain  the 
various  causes  for  the  distribution  of  gold  in  placers, 
for  which  reason  the  ground  must  be  systematically 
sampled. 

At  times  the  gold  will  be  uniformly  distributed  through 
the  dirt,  at  other  times  it  will  be  in  bunches  with  barren 
dirt  above  and  below,  and  in  some  cases  it  will  be  con- 
centrated in  spots  in  a  bench  termed  a  pay  streak.  It 
has  been  found  from  grass  roots  to  bed  rock  but  in  the 
majority  of  cases  the  richest  deposits  are  in  the  latter 
situations.  If  there  be  depressions  in  the  bed  rock 
where  gold  can  accumulate  the  pay  streak  may  be  very 
rich  at  times.  Where  bars  were  formed  in  ancient 
streams  by  eddies,  the  gravel  may  be  very  rich,  hence 
the  necessity  for  carefully  following  the  pay  streak  in 
bench  mining. 

The  thickness  of  placers  will  vary  from  a  few  inches 
to  several  hundred  feet,  and  where  one  deposit  may 
hare  but  a  single  pay  streak,  another  may  have  several. 
From  what  has  been  said  the  reader  evidently  under- 
stands that  the  composition  of  the  placer  dirt  will  vary 
in  different  localities.  The  easiest  dirt  to  wash  is  sandy 
gravel.  Hardpan,  composed  of  gravel  cemented  with 
clay,  is  more  difficult,  for  if  wet  it  is  hard  to  shovel,  and 
if  dry  it  is  difficult  to  pick.  Usually  fine  sand  is  not  as 
rich  as  coarser  sand,  and  to  this  may  be  attributed  some 
of  the  failures  in  dredging  river  bars. 


PLACER  PROSPECTING  9 

The  character  of  the  gold  found  in  placers  is  as  dif- 
ferent as  the  placers.  Coarse  gold  in  nuggets  is  the 
easiest  to  recover,  on  account  of  its  weight  and  shape. 
Flake  gold  is  not  so  easy  to  save  as  nugget  gold;  how- 
ever, its  weight  will  make  it  sink  as  soon  as  it  is  cleaned 
sufficiently  to  prevent  the  water  moving  it.  Leaf  gold 
resembles  flake  gold,  but  is  much  thinner  and  lighter 
and  consequently  will  sink  with  difficulty,  muddy  water 
seemingly  having  sufficient  buoyancy  to  carry  it  away. 
Flour  gold  is  very  fine  gold,  that  may  make  the  assay  of 
a  deposit  run  high;  at  the  same  time  it  is  difficult  to 
save,  and  very  often  it  cannot  be  saved  by  the  hydraulic 
methods  practiced  for  nugget  gold.  The  black  sands 
that  are  usually  found  with  placer  gold  carry  consider- 
able gold  and  frequently  platinum;  therefore,  wherever 
it  is  possible  they  should  be  saved. 

In  Trinity  County,  California,  there  are  both  ancient 
and  present  river  placer  deposits,  the  latter  mostly  de- 
rived from  the  former,  through  the  natural  changes  in 
the  rocks  brought  about  by  time  and  the  elements. 

One  of  the  ancient  river  channels  extends  from  a  few 
miles  north  of  Trinity  Center  southwesterly  to  Junction 
City,  a  distance  of  about  30  miles.  The  bed  rock  of  this 
channel  is  several  hundred  feet  higher  than  the  bed  rock 
of  the  present  Trinity  River  and  the  gravel  is  sometimes 
500  feet  thick,  where  it  has  not  been  affected  by  erosion. 

Gold  is  scattered  through  the  entire  mass  of  alluvium, 
although  as  in  present  rivers  it  is  more  abundant  in 
some  places  than  in  others. 

To  illustrate  the  conditions  prevailing,  assume  that 
Fig.  i  represents  the  cross-section  of  the  country  across 


10 


GEOLOGY   OF   PLACER  DEPOSITS 


several  canons  or  ravines;  then  it  will  be  possible  to 
understand  the  method  of  reaching  the  ancient  river  bed 
by  means  of  tunnels,  H,  driven  at  right  angles  to  the 
course.  The  original  position  of  the  land  is  represented 


FIG.  i. 

by  the  horizontal  line  A  A;  and  it  is  probable  that  the 
rocks  carried  gold.  In  time  this  land  was  eroded  and 
assumed  the  surface  undulations  represented  by  the 
dotted  line  ABA.  In  the  course  of  time,  possibly  many 
centuries,  the  surface  rocks  were  washed  down  from  the 
hills  into  the  valley  B  which  also  formed  a  river  channel. 
During  the  times  of  high  water  the  rocks  in  the  channel 
were  disintegrated  by  water  moving  them  and  causing 
them  to  strike  against  other  rocks  until  the  gold  they 
contained  was  freed,  and  naturally  being  heavier  and  in 
smaller  particles  than  the  rock,  it  settled  to  the  bottom 
of  the  channel.  It  is  probable  that  some  of  the  gold 
traveled  long  distances  before  it  reached  the  place  where 
it  is  now  lodged,  in  fact  there  are  evidences  of  gold  having 
been  carried  several  hundred  miles  before  finding  a  rest- 
ing place.  In  California  after  the  rivers  had  cut  their 
way  through  the  rocks  there  was  an  upheaval  (pre- 


TERTIARY   RIVER   PLACERS  II 

sumably  in  Tertiary  times),  followed  by  a  basaltic  lava 
flow  which  first  filled  the  ancient  river  channels,  and  some- 
times capped  the  hills  above  them.  In  the  epochs  fol- 
lowing the  lava  flow,  that  being  able  to  resist  erosion 
better  than  the  shattered  country  rock,  new  channels 
formed  as  at  EE  shown  by  the  heavy  lines.  These  new 
rivers  may  be  1000  or  more  feet  lower  than  the  lava  cap 
in  some  places,  and  then  again  the  present  river  course 
may  be  above  the  ancient  river  bed,  as  in  Tasmania  and 
the  Klamath  River  District,  California.  In  still  later 
periods  the  new  river  beds  may  have  channels  cut  in 
them,  when  bench  deposits  such  as  are  shown  at  G  will 
be  found. 

The  rim  rock  of  the  rivers  is  the  shore  line  or  country 
rock  each  side  of  the  river  channel,  and  where  there  are 
gulches  at  an  angle  to  the  channel,  tunnels  H  may  be 
driven  to  reach  the  channel  at  B. 

In  Fig.  i,  C  represents  the  lava  cap,  and  D  the  gravel 
deposit  in  the  ancient  river;  G  represents  a  channel  cut 
in  the  present  river  bed  so  as  to  form  the  bench  de- 
posits mentioned. 

According  to  the  United  States  Revised  Statutes  any 
deposit  of  minerals  not  found  in  place  in  veins  in  rock 
are  placers,  therefore  the  descriptive  geology  of  the 
stanniferous  deposits  of  Tasmania  furnished  by  Edward 
Edwards  in  his  Paper  on  Hydraulic  Mining  is  abstracted 
in  part,  first  because  the  geology  is  somewhat  similar  to 
that  of  California,  and  secondly  because  these  tin  deposits 
are  worked  by  hydraulic  mining.1 

The  country  rock  is  granite  which  contains  small  tin 

1  Mines  and  Minerals. 


12  GEOLOGY  OF   PLACER  DEPOSITS 

veins,  or  large  low-grade  deposits  of  tin  in  metamorphosed 
granite  bounded  by  unaltered  barren  granite.  The 
altered  granite  is  coarse  and  probably  would  come  under 
the  head  of  greisen.  In  addition  to  cassiterite,  Sn02, 
it  contains  other  minerals.  The  placer  deposit  having 
been  derived  from  the  greisen  naturally  contains  all  the 
associated  minerals  in  that  rock  which  includes  a  little 
gold  and  petrified  wood;  but  the  mineral  sought  and 
recovered  is  the  tin  oxide.  If  any  other  minerals  are 
saved,  they  are  by-products.  While  basaltic  flows  cov- 
ered the  ancient  river  channels  they  seem  not  to  have 
been  so  copious  as  those  of  California  as  they  do  not 
cover  the  surrounding  hills. 

In  Fig.  2  is  shown  how  the  basaltic  flows  a  covered  the 
ancient  river  gravel  b  and  protected  it  from  erosion. 


FIG.  2. 

Evidently  the  eruptions  were  not  confined  to  one  out- 
burst, for  at  a  drift  accumulated  between  the  lava  layers. 
This  drift  also  proves  that  the  river  occupied  its  course 
after  the  first  eruption,  but  that  after  the  final  lava  flow 
the  river  and  its  tributaries  were  displaced  and  forced 
into  other  channels  as  at  c.  In  most  cases  these  channels 
were  to  one  side  of  the  lava  and  commencing  at  the  un- 
altered country  rock  a  new  channel  was  started  as  at/, 
Fig.  3,  on  the  assumption  that  e  was  the  level  of  the  basalt. 


TERTIARY  RIVER   PLACERS  13 

The  Ringaroom  River  which  it  is  believed  had  its 
commencement  at  /  gradually  eroded  the  lava,  but  not 
the  hard  country  granite  rock  to  so  great  an  extent,  until 
it  reached  its  present  position  c  in  Fig.  3.  It  will  be 
noticed  that  the  river  has  reached  the  gravel  deposit 


FIG.  3. 

and  moved  it  to  places  where  later  banks  have  been 
made,  some  as  high  as  100  feet,  and  it  is  these  banks  of 
alluvial  material  on  which  placer  mining  is  practiced. 
Those  portions  of  the  deposits  below  river  level  are 
worked  by  dredges. 

Waters  percolating  through  the  altered  basalt  leached 
out  iron  and  this  converted  the  drift  below  into  a  hard 
cement  of  a  red-brown  color,  the  same  in  appearance  as 
the  weathered  basalt. 

The  remainder  of  the  river  drift  consists  of  white  sand 
and  granite  boulders  with  here  and  there  layers  of  white 
clay  derived  from  the  feldspar  of  the  granite.  This  clay 
would  indicate  from  its  presence  in  the  wash  that  there 
were  periods  of  tranquil  sedimentation  which  assumption 
is  substantiated  by  the  absence  of  tin  oxide  and  other 
heavy  minerals. 


14  GEOLOGY   OF   PLACER   DEPOSITS 

Tin  oxide  or  cassiterite  has  a  density  of  6.4  to  6.9 
according  to  its  purity,  and  because  of  being  much 
heavier  than  more  common  minerals  it  sinks  and  remains 
motionless  while  the  others  are  swept  along  by  the  flowing 
river. 

The  oxide  is  found  scattered  through  the  whole  gravel 
deposit,  and  in  nearly  horizontal  layers  although  as  a 
rule  the  drift  is  richest  along  the  bottom  of  the  river  bed; 
however  the  quantity  varies  both  across  and  along  the 
deposit. 

The  ore  is  fairly  uniform  in  size  and  is  of  excellent 
quality,  the  concentrates  assaying  75  per  cent  tin  which 
is  the  equivalent  of  95  per  cent  cassiterite. 

Waldmer  Lindgren  of  the  United  States  Geological 
Survey  studied  the  Tertiary  placer  deposits  of  the  Sierra 
Nevada  mountains  in  California  and  presented  his  find- 
ings in  Professional  Paper  No.  72  of  the  Survey.  Be- 
cause of  the  difficulty  of  obtaining  this  paper  at  this  time, 
at  least  by  many,  the  following  is  abstracted. 

"A  basement  of  closely  folded  Paleozoic  and  Meso- 
zoic  sedimentary  rocks  was  intruded  and  elevated  near 
the  close  of  the  Mesozoic  Period  by  granitic  magmas. 
This  was  followed  closely  by  the  introduction  of  veins 
and  seams  of  gold  bearing  quartz.  The  resulting  high- 
land was  planed  down  by  erosion  in  early  cretaceous 
times.  When  reduced  to  gentle  outlines  deep  rock  decay 
took  place  and  much  gold  was  freed  from  its  matrix. 
Renewed  uplifts  quickened  erosion  which  concentrated 
the  loosened  gold  along  definite  channels.  During  this 
period  of  most  active  gold  concentration  faulting  move- 
ments with  downthrow  on  the  east  side,  transformed  an 


TERTIARY   RIVER   PLACERS  15 

approximately  symmetrical  range  to  a  monoclinal  one 
with  steep  easterly  slope.  Towards  the  end  of  the  Terti- 
ary Period  long  inactive  volcanic  forces  became  active. 
Rhyolite  flows  filled  the  valleys,  covered  the  auriferous 
gravels  and  outlined  new  stream  courses  in  the  old  val- 
leys. Renewed  disturbance  began  along  the  scarcely 
healed  eastern  breaks  resulting  in  a  westward  tilting  of 
the  main  blocks.  This  encouraged  deeper  cutting  by 
the  streams  which  repeatedly  crossed  their  old  courses, 
and  concentration  of  gold  proceeded  under  less  favorable 
torrential  conditions. 

Volcanoes  sent  out  immense  quantities  of  tuff,  filling 
many  valleys  to  their  rims  and  converting  almost  all  of 
the  northern  Sierra  into  a  desolate,  steaming  expanse 
of  mud.  Storm  waters  now  began  the  canon  cutting 
epoch,  with  the  amazing  results  seen  to-day.  In  many 
places  the  old  rivers  of  the  Tertiary  were  exposed  and 
cross  sections  of  their  valleys  are  now  seen  on  the  steep 
slopes  of  the  canons  high  above  the  present  river  beds: 
although  large  stretches  of  the  old  channels  remained 
secure  below  their  thick  blanket  of  volcanic  mud. 

Gold  is  still  contained  in  the  Tertiary  river  channels, 
miles  of  them  are  still  unworked,  but  the  problem  is 
how  to  extract  without  damage  to  other  property  and 
how  to  reduce  -the  cost  of  drift  mining.  The  gold  of  the 
larger  channels  is  about  the  size  of  flaxseed,  although 
large  nuggets  are  occasionally  found,  that  from  Carson 
Hill  weighing  195  pounds  Troy.  Only  recently  one  was 
taken  from  the  Emma  Mine  near  Magalia  that  weighed 
50  ounces.  The  general  channels  yield  from  $70  to  $500 
to  the  lineal  foot,  which  may  be  compared  with  $100  per 


16  GEOLOGY   OF   PLACER  DEPOSITS 

foot  at  Nome,  Alaska,  $350  a  foot  in  White  Channel  in 
the  Klondike,  and  $440  to  $1293  in  the  Berry  drift  mine 
in  Australia." 

Hydraulicking  on  the  tributaries  of  the  Sacramento 
River  in  California  was  stopped  by  the  courts  previous 
to  1893,  owing  to  the  great  quantity  of  dirt  which  was 
carried  down  the  rivers  and  deposited  as  silt  on  the  farm 
lands.  The  Klamath  River  field  is  now  we  believe  the 
only  district  in  California  where  hydraulicking  is  prac- 
ticed. The  Caminette  Act  of  1893  which  demanded  the 
impounding  of  debris  from  the  placers  of  the  San  Joaquin 
and  Sacramento  valleys,  does  not  affect  any  other  part 
of  the  state  as  most  rivers  flow  directly  to  the  sea.  The 
deposit  being  mined  is  an  ancient  channel  of  the  Klamath 
River  which  had  a  flow  nearly  parallel  to  the  present 
river,  but  at  considerably  less  elevation  relative  to  the 
sea  level.  The  old  channel  varies  in  width  from  100  to 
600  feet,  and  possibly  more,  for  the  channel  seems  to  be 
widening  as  work  progresses.  Granite  and  schists  are  the 
prevailing  country  rocks  with  the  bed  rock  a  hard  schist 
rough  and  water  worn  with  soft  shale  streaks  at  intervals. 
The  shale  being  tilted  forms  an  excellent  riffle  for  gold 
moving  along  the  bottom.  In  cleaning  this  shale  it  is 
not  stripped  bare  by  the  giant  because  that  breaks  the 
rock  and  the  gold  sinks  into  the  cracks  made.  Men 
therefore  pick  the  shale  at  right  angles  to  the  dip  to 
a  depth  of  about  two  feet,  the  object  being  to  prevent 
the  gold  from  sinking  deeper  as  would  be  the  case  if  the 
picking  were  done  parallel  to  the  dip. 

The  hard  slate  bed  rock  is  pipe-washed  clean,  the 
crevices  only  being  cleaned  by  hand.  At  the  contact  of 


DRY   PLACERS  17 

the  schist  and  shale  there  is  a  blue  clay  which  if  not 
broken  to  mud  will  carry  gold  through  the  sluices  and 
prevent  its  entering  the  riffles.  The  bed  rock  is  on  an 
average  about  20  feet  below  the  surface,  and  although 
the  pay  streak  has  an  average  thickness  of  10  feet  the 
best  ground  is  within  5  feet  of  the  bed  rock. 

It  has  been  noted  that  the  higher  the  gold  is  from  bed 
rock  the  lighter  and  purer  it  is. 

The  pay-streak  gravel,  dark  blue  in  color,  consists  of  a 
mixture  of  heavy  water-rounded  rocks  and  wash  material. 
Owing  to  the  sulphides  in  the  country  rocks  the  water 
coming  through  the  cracks  in  bed  rock  is  very  corrosive, 
being  charged  with  arsenic  and  iron  sulphates  in  solution. 
When  this  water  comes  in  contact  with  the  metal  in  the 
pipes  it  quickly  corrodes  them  unless  they  are  painted  as 
in  other  places  mentioned. 

Dry  Placers.  —  Dry  placers  have  been  mentioned 
as  occupying  large  areas  in  the  southwestern  states  and 
Mexico.  These  were  formed  by  rivers  evidently  of  the 
Tertiary  period  or  later,  which  flowed  southwest  from 
the  Rocky  and  south  from  the  Sierra  mountains. 

The  ground  in  which  the  placers  are  found  is  not  deep 
and  is  composed  of  sandy  clay.  South  from  the  Pima 
Desert  in  Arizona  there  extends  a  large  area  of  this  dry 
placer  material  which  in  Sonora,  Mexico,  is  called  the 
Altar  District.  In  an  area  between  the  Magdalena 
River  and  the  Gulf  of  California  there  is  about  9600 
square  miles  of  dry  placer  material  which  is  brought 
to  the  attention  of  the  public  every  few  years  by  the 
man  who  has  invented  a  new  machine  to  treat  this 
ground. 


i8  GEOLOGY   OF   PLACER   DEPOSITS 

These  dry  placers  were  discovered  by  Spanish  soldiers 
in  1779  and  rediscovered  in  1840,  again  in  1892  and  more 
recently  in  1908;  in  the  meantime  they  were  never  lost 
sight  of  from  the  time  of  their  earliest  discovery  and  are 
worked  off  and  on  by  the  native  Indians. 

While  as  a  rule  these  deposits  are  not  deep,  rich  ground 
has  been  found  when  digging  wells  to  a  depth  of  90  feet. 
The  gold  is  found  in  clay  that  accompanies  cement  gravel 
and  to  disintegrate  this  material  and  free  the  gold  with- 
out the  aid  of  water  is  a  problem  which  inventors  have 
had  in  mind  many  years ;  therefore  when  a  new  machine 
is  invented  for  the  purpose  the  placers  are  rediscovered. 
Unfortunately  dry  placer  machines,  except  small  ones 
worked  by  hand,  require  more  or  less  water;  even  for  the 
gas  or  oil  engine  used  for  power  and  consequently  they 
have  not  yet  come  into  general  use.  The  writer  believes 
that  water  can  be  found  by  digging  wells  at  almost  any 
place  in  the  southwest  provided  a  dry  river  bed  or  stream 
is  the  ground  in  which  the  well  is  sunk.  This  is  somewhat 
substantiated  by  his  experience  in  Arizona  and  the  fact 
that  between  hills  in  the  Altar  district  where  the  drainage 
collects,  well  water  is  found  at  depths  from  150  to  300  feet 
below  the  surface.  The  Altar  and  Magdalena  Rivers, 
which  are  usually  dry,  sometimes  have  water  flowing  in 
their  channels  during  the  rainy  season.  It  is  also  natural 
to  suppose  that  there  are  underground  watercourses 
along  the  ancient  sea  floor  that  flowed  westward  into  the 
Gulf  of  California. 

The  author  makes  these  remarks  because  he  believes 
that  the  first  problem  to  solve  in  order  to  work  these 
placers  is  that  of  water  supply;  even  if  it  is  not  large 


PLACER   PROSPECTING  19 

and  is  alkali  it  will  go  a  long  way  towards  making 
these  placers  productive. 

There  are  so  many  places  in  the  southwestern  states 
where  gold  exists  that  this  subject  of  location  might  be 
continued  almost  indefinitely.  Some  of  them  will  be 
mentioned  further  on  in  this  book. 


PLACER  PROSPECTING. 

The  prospector,  in  working  upstream  in  his  quest 
for  gold,  finds  in  panning  tests  some  places  richer  in  gold 
than  others. 

If  he  can  make  money  washing  one  of  these  pockets 
he  is  said  to  have  "  pay  dirt."  Although  gold  is  dissemi- 
nated in  some  cases  throughout  the  entire  mass  of  gravel 
of  a  large  placer  deposit,  nevertheless  there  are  places 
where  the  gold  is  in  greater  abundance  than  in  others. 
Early  prospectors  sought  these  enriched  places  and  the 
present  hydraulic  miners  find  many  indications  in  the  way 
of  abandoned  drifts  and  old  shafts  mute  evidence  of  the 
pocket  miner's  zealous  hunt  for  wealth.  The  prospector 
with  little  money,  his  tools  being  limited  to  pick,  pan  and 
shovel,  is  unable  to  attack  a  deposit  of  this  kind  from  the 
top  where  bed  rock  may  be  covered  many  feet  with  gravel; 
consequently  having  become  familiar  with  the  kind  of 
material  and  rocks  in  the  channel  at  some  place  where 
it  is  exposed  he  follows  the  rim-rock.  When  he  finds  a 
gulch  or  ravine  at  an  angle  to  the  ancient  river  he  com- 
mences to  drive  from  the  gulch  so  as  to  tap  the  gravel 
bed  with  a  drift. 

After  he  finds  the  gulch  he  pans  the  dirt  upstream  and 


20  GEOLOGY  OF   PLACER  DEPOSITS 

continues  to  do  so  until  he  comes  to  a  place  where  he  can 
attack  the  channel. 

Sometimes  the  lead  he  follows  is  so  rich  in  gold  he  pays 
his  way  while  searching;  in  other  cases  he  may  keep  up 
the  hunt,  although  he  does  not  recover  much  gold,  being 
buoyed  by  the  hope  of  eventually  finding  a  pocket. 
When  the  streams  are  comparatively  large  the  task  of 
following  them  to  reach  the  ground  is  easy ;  where  how- 
ever the  prospector  has  to  carry  dirt  some  distance  to 
water  in  order  to  wash  it  the  work  becomes  very  difficult. 
Experienced  prospectors  looking  for  placers  will  pass  by 
gold  which  on  examination  shows  that  it  came  from  veins 
in  recent  times,  as  he  knows  from  the  appearance  of  the 
gold  that  the  ground  has  little  value.  The  distinguishing 
features  are  that  vein  gold  is  fine  and  angular,  whereas 
placer  gold  is  usually  coarser  and  water-rounded. 

This  experienced  miner,  by  the  use  of  judgment,  is 
thus  kept  from  following  a  false  trace  that  comes  from 
some  vein  in  the  country  rock. 

The  prospector  having  made  a  discovery  is  entitled  to 
20  acres  of  placer  land,  but  he  should  be  sure  that  the 
claim  has  not  been  staked  previously  or  that  he  is  not  on 
some  land  grant  before  he  does  much  work  in  develop- 
ing. It  may  be  stated  here  that  very  many  claims 
have  been  located  by  prospectors  who  worked  them  to 
some  extent  and  obtained  considerable  gold  from  them. 
These  claims  are  held  by  heirs  or  others  at  exorbitant 
prices,  when  the  amount  of  money  involved  to  work 
them  successfully  is  considered  in  addition  to  the  risk, 
for  which  reason  they  remain  and  are  likely  to  remain 
idle  indefinitely. 


WATER   RIGHTS  21 

There  are  two  factors  to  hydraulicking  fully  as  im- 
portant as  the  placer  deposit,  namely :  a  sufficient  supply 
of  water  and  a  dumping  ground;  if  these  are  lacking 
the  deposit  will,  unless  very  rich  and  otherwise  mined, 
prove  unremunerative.  The  first  consideration  is  water 
and  for  this  purpose  the  owner  of  a  claim  is  entitled  to 
water  rights  under  certain  restrictions.  Revised  Stat- 
utes of  the  United  States  in  Section  2339,  provides  that, 
"  Whenever  by  priority  of  possession,  rights  to  the  use 
of  water  for  mining,  agriculture,  manufacturing,  or  other 
purposes,  have  vested  and  accrued,  and  the  same  are 
recognized  and  acknowledged  by  local  customs,  laws, 
and  decisions  of  courts,  the  possessors  and  owners  of  such 
vested  rights  shall  be  maintained  and  protected  in  the 
same;  and  right  of  way  for  the  construction  of  ditches 
and  canals  for  the  purpose  therein  specified  is  acknowl- 
edged and  confirmed;  but  whenever  any  person,  in  the 
construction  of  any  ditch  or  canal,  injures  or  damages 
the  possession  of  any  settler  on  the  public  domain  the 
party  committing  the  damage  shall  be  liable  to  the  party 
injured  or  damaged  ";  and  Section  2340  provides  "  That 
all  patents  granted  or  pre-emption  of  homesteads  allowed, 
shall  be  subject  to  any  vested  and  accrued  water  rights, 
or  rights  to  ditches  and  reservoirs  used  in  connection 
with  such  water  rights,  as  may  have  been  acquired  under, 
or  recognized  by  the  preceding  section." 

State  laws  relating  to  water  rights  are  also  to  be 
considered;  for  instance  the  California  law  requires  the 
person  making  the  appropriation  to  post  a  notice  at  the 
point  of  the  intended  diversion,  stating  thereon : 

i.   That  he  claims  the  water  there  flowing  to  the 


22  GEOLOGY   OF   PLACER   DEPOSITS 

extent  of  ...  miner's  inches  measured  under  a  four-inch 
head. 

2.  The  purpose  for  which  it  is  claimed  and  the  place 
of  intended  use. 

3.  The  means  by  which  he  intends  to  divert  it,  the 
size  of  the  flume,  ditch,  pipe,  or  aqueduct  in  which  he 
intends  to  convey  the  water. 

Montana  has  a  somewhat  different  law,  consequently 
the  claimant  to  water  rights  must  familiarize  himself 
with  these  state  laws. 

The  object  in  prospecting  placers  known  to  contain 
gold  or  other  minerals  is  to  estimate  the  probable  quantity 
of  earth  that  must  be  moved,  its  average  value  in  min- 
erals sought,  and  from  this  data  to  calculate  the  money 
it  is  allowable  to  spend  on  development  to  make  a  profit 
on  the  investment.  To  estimate  the  quantity  of  gravel 
in  a  property  contour  surveys  of  the  surface  are  required, 
together  with  the  thickness  of  the  dirt  in  a  given  area. 
The  latter  is  found  by  putting  down  lines  of  boreholes  at 
regular  intervals  from  the  surface  to  bed  rock  or  by  sink- 
ing shafts. 

To  ensure  that  the  holes  reach  bed  rock  and  are  not  in 
a  large  boulder  it  is  probably  advisable  to  sink  them  at 
least  10  feet  into  bed  rock. 

The  driller  can  usually  tell  by  feeling  the  drill  rods 
whether  his  drill  is  in  a  boulder  or  bed  rock;  he  is  further 
guided  by  the  depth  of  his  hole  relative  to  another  in  a 
similar  line;  however,  the  plan  suggested  may  be  advis- 
able because  it  becomes  surer  that  no  large  rock  is  mis- 
leading the  driller. 

If  the  pay  streak  is  near  bed  rock  and  the  drill  hap- 


CALCULATING   PLACER   GROUND  23 

pened  to  land  on  a  large  stone  near  bed  rock  the  gold 
would  not  show,  but  even  then  there  would  be  the  satis- 
faction in  knowing  that  the  blank  was  probably  due  to 
the  boulder  and  not  because  the  place  was  barren. 

After  the  holes  have  been  drilled  their  positions  on  the 
map  are  plotted  accurately  with  reference  to  the  con- 
tours mentioned. 

Where  the  bed  rock  is  uneven  either  of  the  following 
methods  may  be  used: 

1.  The  area  is  divided  by  lines  connecting  adjacent 
boreholes  thus  forming  squares.     The  depths  of  the  holes 
and  the  areas  of  the  squares  are  then  used  to  calculate 
the  volume  of  the  gravel  bed.     The  depth  of  the  hole  in 
feet  is  placed  on  the  map  as  shown  in  Fig.  5. 

2.  In  the  second  method  contour  lines  are  drawn  at 
regular  intervals  of  depth,  the  areas  enclosed  are  then 
found  with  a  planimeter,  and  the  volume  between  every 
two  adjacent  contours  is  computed  by  multiplying  the 
mean  area  by  the  contour  interval. 

The  use  of  prismoidal  formulae,  advocated  by  some 
engineers  to  replace  the  mean  average  method,  is  a  re- 
finement generally  not  justified  in  this  kind  of  work  on 
account  of  the  comparatively  few  points  actually  deter- 
mined, and  the  large  amount  of  assumption  needed  in 
interpolating  the  remaining  points  and  contour  lines; 
further,  as  will  be  shown  later  on,  the  accuracy  of  the 
method  has  not  proved  more  valuable  than  the  mean 
average  method  explained  in  this  text. 

The  method  of  estimating  the  overburden  by  cross- 
sections  used  at  some  of  the  large  placer  mines  is  shown 
in  Fig.  4,  where  a  represents  barren  ground;  6,  the  gold- 


GEOLOGY  OF  PLACER  DEPOSITS 


bearing  gravel;  c,  a  series  of  boreholes  across  the  deposit 
from  rim-rock  to  rim-rock  or  as  far  as  the  property  ex- 
tends laterally;  while  the  figures  i,  2,  3,  etc.,  represent 
the  distances  between  boreholes. 


FIG.  4. 

From  the  data  thus  acquired  and  the  surface  levels 
a  general  idea  of  any  cross-section  is  obtained,  relative 
to  both  depth  and  volume  of  the  cover  and  placer  ground. 
The  method  of  recording  this  data  is  shown  in  the  fol- 
lowing table: 


Area. 

i 

2 

3 

4 

5 

6 

7 

Elev.  surface 

316 
312 

2 
O 

327-4 
307.4 
293-4 

34 

14 
142 

334-2 
303.7 
276.7 

57-5 
27 
106 

340.7 
303-0 
261  .0 
79-7 
42 
216 

340.6 
303-7 
258-7 
81.9 

45 
280 

330.1 
305-1 
268.1 
62  .0 
37 
350 

328-318 

307.3 
282.3-318 

45-7 
25 

200 

Elev.  top  drift  
Elev.  bedrock  
Depth  of  cover  
Depth  of  gravel.  .  .  . 
Value  of  gold  

Borehole  No  

Estimating  the  Value  of  Placers.  —  Sampling  placer 
deposits  is  important,  because  on  the  values  obtained 
the  profits  of  the  plants  will  be  based,  and  if  the  operation 


ESTIMATING   PLACERS  25 

is  not  properly  performed  in  low-grade  deposits,  the 
value  of  a  few  cents  per  cubic  yard  may  cause  the 
loss  of  large  sums  of  money.  The  methods  followed  in 
arriving  at  the  value  of  a  deposit  are  enumerated  as 
face  sampling;  tunnel  and  drift  sampling;  borehole  sam- 
pling; shaft  sampling;  bulk  tests  under  working  condi- 
tions. In  general  a  test  consists  in  obtaining  a  known 
quantity  of  the  material;  washing  it  to  recover  the  gold; 
weighing  the  latter  and  multiplying  this  weight  by  the 
fineness  of  the  gold  value,  which  if  taken  at  $18  per  Troy 
ounce  will  approximate  the  value,  however,  as  the  fine- 
ness of  gold  varies  in  different  deposits  the  actual  value 
per  ounce  had  better  be  determined  by  the  Assayer. 

If  the  sample  taken  is  small  the  dirt  is  panned;  if  larger 
a  rocker  may  be  used;  or  if  quite  large  it  is  sluiced  and 
by  this  means  the  returns  will  approximate  what  may  be 
expected  in  actual  working. 

Of  the  three  methods,  that  of  panning  is  probably  the 
most  accurate  when  done  by  an  expert,  but  it  is  advis- 
able to  treat  the  whole  sample  in  any  case,  because 
smaller  samples  taken  from  larger  ones  nearly  always 
underestimate  the  gold.  Two  troubles  confront  the 
man  taking  the  sample:  namely,  the  irregular  dis- 
tribution of  the  gold,  and  ascertaining  the  true  volume 
occupied  by  the  sample  when  it  is  in  the  ground.  The 
best  method  of  arriving  at  the  size  of  the  sample  is  to 
make  use  of  measures  of  known  capacity  and  then  make 
allowance  for  the  increase  in  bulk.  Different  kinds  of 
material  differ  in  volume  when  broken  according  to  the 
size  of  the  pieces,  therefore  the  surest  way  of  arriving  at 
a  bulk  factor  is  to  carefully  mark  off  a  portion  of  the 


26  GEOLOGY   OF   PLACER  DEPOSITS 

ground  and  measure  it  in  the  solid,  then  after  the  exca- 
vation is  made  measure  the  broken  ground  in  boxes 
whose  capacity  is  known.  When  it  is  possible  to  drive  a 
powder  can  into  the  dirt  face,  a  fair  sample  will  be  had  be- 
cause when  withdrawn  the  can  will  retain  the  original 
volume  cut.  The  dirt  when  tipped  from  the  can  is  broken 
and  remeasured  and  the  increased  bulk  is  then  expressed 
as  so  much  per  cent  of  the  original.  The  mean  of  several 
such  determinations  furnishes  a  factor  that  may  be 
applied  to  large  samples  or  bulk  tests.  The  increase  in 
bulk  will  vary  from  20  per  cent  for  fine  material  to  50  per 
cent  for  coarse  material.  Face  sampling  while  having 
the  advantage  of  cheapness  is  not  apt  to  give  accurate 
values  because  of  the  difficulty  in  taking  a  representative 
sample;  the  practice  is  followed,  however,  in  preliminary 
work,  and  when  care  is  practiced  it  furnishes  a  fair  aver- 
age of  the  deposit;  at  least  it  will  indicate  the  necessity 
for  further,  more  accurate  and  expensive  tests. 

One  method  followed  in  sampling  a  bank  or  face  is 
to  clean  off  the  weathered  exterior  from  the  top  to  the 
bottom  of  the  bed  by  making  a  cut  two  or  three  feet  wide 
and  sufficiently  deep  to  reach  fresh  dirt. 

This  precaution  is  taken  because  natural  concentra- 
tion occurs  at  the  surface.  In  case  the  bank  is  high 
some  means  for  reaching  the  entire  surface  must  be  de- 
vised. Either  a  ladder  may  be  lowered  from  the  top  or 
raised  from  the  bottom  to  the  place  sampled,  or  possibly 
a  series  of  side  steps  can  be  made  along  the  bank.  In 
the  latter  case  close  measurements  must  be  taken  hori- 
zontally to  prevent  the  steps  overlapping. 

This  latter  consideration  arises  from  the  tendency  of 


SAMPLING    PLACERS  27 

gold  to  accumulate  in  layers  and  at  about  the  same  gen- 
eral horizon  relative  to  bed  rock.  In  comparison  with  the 
remainder  of  the  deposit  such  streaks  are  rich,  yet,  being 
thin,  to  miss  or  to  overlap  them  will  give  false  values. 

After  the  face  has  been  prepared  the  samples  are  taken 
from  bed  rock  upwards  by  measuring  off  one  foot  in  height 
and  putting  in  a  small  wooden  peg  as  a  marker  for  the 
next  sample.  The  pan  is  held  at  the  bottom  of  the  place 
being  sampled  and  the  material,  broken  from  the  bed  by 
a  small  pole  pick,  falls  into  the  pan.  The  sample  should 
be  taken  up  and  down  the  first  foot  section  in  straight 
lines  and  to  an  equal  depth,  going  around  stones  over 
three  inches  in  diameter  or  which  do  not  work  loose  from 
the  face.  Owing  to  the  edge  of  the  pan  being  circular 
and  the  face  generally  more  or  less  inclined  the  pan  be- 
comes heavy  if  large  and  the  dirt  is  apt  to  miss  the  pan, 
for  which  reason  some  one  must  hold  the  pan  and  it  is 
also  advisable  to  have  a  funnel  with  one  side  flattened  to 
go  against  the  bank  while  the  spout  directs  the  dirt  to 
the  center  of  the  pan.  This  spout  may  have  as  large  a 
diameter  as  three  inches,  to  catch  any  large  stones  that 
may  fall  from  the  bank  cut,  for  if  such  stones  fall  into 
the  pan  they  dislodge  dirt  and  sometimes  cause  the  con- 
tents to  spill. 

Material  broken  at  a  face  2  ft.  X  i  ft.  X  2\  in.  deep 
will  occupy  a  space  say  \  cubic  feet  or  about  i\  times 
what  a  pan  16  X  10  X  2\  in.  high  will  hold.  It  may  be 
advisable  therefore  to  use  a  canvas  basket  for  this  kind 
of  work  as  it  will  lessen  the  labor  and  furnish  more  ac- 
curate data  on  the  volume  of  the  sample. 

The  number  of  pans  filled  evenly  with  the  top  that  will 


28  GEOLOGY   OF   PLACER   DEPOSITS 

constitute  a  cubic  yard  in  place  varies  with  the  degree 
of  coarseness  of  the  dirt;  for  instance,  where  one  cubic 
yard  of  gravel  will  fill  70  pans,  one  cubic  yard  of  gravel 
in  another  bench  will  possibly  fill  150  pans  evenly  with 
the  top.  It  may  be  understood  from  this  that  the  factor 
for  measuring  by  the  pan  is  of  even  more  importance 
than  where  measures  are  made  in  larger  bulks;  however, 
estimations  are  frequently  made  by  pans.  After  the 
gravel  is  broken  from  the  face  for  the  length  of  one  foot, 
it  is  carried  to  water  and  panned.  If  the  gold  is  coarse  the 
number  of  pieces  are  counted,  but  where  fine  this  is  im- 
possible and  the  gold  with  the  accompanying  black  sand  is 
saved.  When  the  prices  are  counted,  the  position  of  the 
sample  is  recorded  and  its  bulk  estimation  as  well.  The 
next  foot  of  ground  in  the  face  is  sampled  in  the  same  way 
and  so  upwards  until  the  top  is  reached.  If  the  bank  is 
fairly  uniform  the  gold  from  each  successive  foot  may  be 
placed  in  a  small  vessel  for  weighing  provided  it  is  so 
coarse  it  may  be  separated  from  the  dirt  in  the  pan;  on 
the  contrary,  if  it  is  so  fine  that  it  cannot  be  separated  it  is 
collected  with  mercury.  If  the  gold  and  accompanying 
black  sand  were  assayed,  the  value  of  the  ground  as  a 
placer  could  not  be  estimated,  for  black  sand  frequently 
contains  considerable  gold  that  can  only  be  recovered  by 
furnace  treatment.  If  the  ground  forming  the  bank  is 
in  layers  of  different  kinds  of  material  each  layer  should 
be  kept  separate  so  that  each  may  be  valued. 

To  calculate  the  sample  and  its  value  the  gold  is 
cleaned,  weighed  and  the  weight  multiplied  by  the  fine- 
ness of  the  gold  estimated  in  cents. 

In  this  connection  it  may  be  stated  that  some  make 


ESTIMATING  GOLD  IN  PLACERS 


29 


use  of  the  gram  and  others  make  use  of  the  grain  in  cal- 
culations. The  gram  weighs  15.432  grains.  The  value 
in  cents  is  next  divided  by  the  number  of  pans  washed 
and  the  bulk  of  the  sample  estimated  in  cubic  yards, 
which  will  give  in  the  aggregate  the  value  of  the  bank  in 
cents  per  cubic  yard.  To  illustrate  this  method,  assume 
the  height  of  the  gravel  deposit  to  be  35  feet  and  that  it 
is  divided  into  three  well-defined  stratum  10,  14  and  n 
feet  thick. 

From  the  lo-foot  stratum  10  pans  were  taken  and  the 
broken  material  averaged  70  pans  to  the  yard.  The  14- 
foot  stratum  required  but  40  pans  to  the  yard  and  the 
1 1 -foot  stratum  70  pans  per  yard.  The  gold  recovered 
when  weighed  and  estimated  was  found  to  be  871  fine 
and  worth  $18  per  ounce  or  0.0578  cent  per  milligram. 
With  this  data  the  following  table  is  computed. 


Stratum. 

Mg.  Gold. 

Value  in 
Cents. 

Pan  Value 
in  Cents. 

Value  per  Cubic 
Yard  in  Cents. 

Ft. 
10 

14 
ii 

30-4 
160.0 
64.0 

1.76 
9-25 
3-7o 

0.176 
0.660 
0.180 

0.176  X  70  =  12.3 
0.660  X  40  =  26.4 
0.180  X  70  =  12.6 

To  obtain  the  bank  value  the  results  are  averaged  by 
taking  into  account  the  value  and  thickness  of  the  strata: 
Thus  I0  x  12.3  123.0 

14  X  26.4  369.6 

ii  X  12.6  138.6 

35  631.2 

631.2  -T-  35  =  18.03  cents  per  cubic  yard  as  the  average 
value  of  the  bank. 


30  GEOLOGY  OF   PLACER   DEPOSITS 

The  method  of  testing  described  is  applicable  to  banks 
and  stopes  in  drift  mines  where  the  exposure  is  fairly 
steep,  particularly  where  the  gold  is  in  more  than  one 
layer  of  gravel. 

A  somewhat  similar  though  more  exact  method  is  that 
of  measured  cuts,  where  the  gold  contained  in  a  known 
volume  of  gravel  measured  in  place  is  ascertained  by 
careful  washing.  Since  the  gold  obtained  is  from  the 
gravel  in  place  the  uncertain  estimate  of  the  expansion 
of  broken  material  is  obviated.  In  this  case  the  bank  to 
be  sampled  is  cleaned  as  in  the  pan  method  from  top  to 
bottom,  the  width  being  such  that  one  foot  at  least  is 
left  each  side  of  the  proposed  cut.  Sample  cutting  com- 
mences at  bed  rock,  then  by  working  a  predetermined 
width  and  depth  it  proceeds  upwards.  Usually  a  cut 
2  feet  wide  and  i|  feet  deep  is  taken  by  first  picking  from 
the  center  line  of  the  cut  and  when  approaching  within 
three  inches  of  the  sides  care  is  taken  to  trim  to  the  exact 
width  of  two  feet,  and  also  reach  the  exact  depth. 

A  template  will  obtain  accuracy  in  width  and  depth 
but  a  center  line  should  be  used  to  keep  the  cut  straight. 
When  collecting  a  sample  in  this  way  a  canvas  sheet  is 
spread  at  the  bottom  of  the  cut  to  prevent  the  gravel 
scattering  and  it  may  be  advisable  to  place  a  canvas  over 
the  cut  to  confine  the  broken  material  within  the  cut, 
thus  forming  a  sort  of  chute.  If  it  is  impossible  to  make 
a  continuous  cut  from  the  top  to  the  bottom  then  the 
engineer  will  have  to  devise  some  means  whereby  he  can 
obtain  samples  which  would  approximate  such  a  cut, 
taking  care  not  to  omit  or  to  overlap  any  part  of  the 
bank. 


ESTIMATING  GOLD  IN  PLACERS      31 

The  gravel  obtained  from  the  cuts  has  considerable 
bulk  and  may  be  washed  in  the  rocker  or  sluice,  the 
gold  recovered,  cleaned  and  weighed  and  calculated  to 
its  bank  value.  If  the  bank  were  30  feet  high  then  the 
material  cut  would  be  1.5  X  2  X  30  =  90  cu.  ft.;  and 
if  the  gold  in  this  material  returned  20.67  cents  the  bank 
value  would  be  found  by  the  proportion  90  :  27  ::  20.67  : 
6.198  cents  per  cubic  yard. 

A  deposit  of  gravel  tested  by  a  sufficient  number  of 
cuts  so  as  to  obtain  a  fair  average  sample  and  value  will 
closely  approximate  the  true  value  of  the  deposit  in  the 
places  sampled,  but  where  no  exposure  exists  the  value 
of  the  deposit  back  from  the  face  is  to  be  determined. 
This  is  accomplished  either  by  a  series  of  drill-holes  or  by 
sinking  shafts.  In  some  cases  shafts  may  be  excavated 
from  the  surface  and  drifts  branched  each  way  from  the 
shaft  bottom  or  it  may  be  possible  where  the  pay  streak 
is  near  bed  rock  to  drift  in  from  the  side  or  along  the 
bed  rock.  To  dig  a  shaft  where  from  two  to  four  feet 
of  water  is  flowing  near  bed  rock  and  obtain  samples 
that  will  approximate  true  conditions  is  practically  a 
physical  impossibility;  or  if  wet  running  ground  is  met 
in  sinking  a  shaft  the  expense  will  become  so  great  that 
some  other  method  must  be  adopted,  such  as  driving  a 
casing  pipe  from  the  surface  to  bed  rock.  The  results 
obtained  at  times  from  shaft  tests  have  frequently  been 
very  close  to  those  obtained  under  subsequent  working 
conditions,  but  it  is  believed  that  they  are  more  useful 
in  shallow  ground  where  there  are  no  watercourses  to 
interfere  with  their  excavation  or  the  recovery  of  test 
ground. 


32  GEOLOGY   OF   PLACER   DEPOSITS 

Shafts  have  the  following  points  in  their  favor:  (i) 
They  furnish  a  large  sample  which  may  give  more 
accurate  returns  than  drill-holes. 

(2)  The  size  of  the  excavation  offers  an  opportunity  to 
thoroughly  inspect  the  ground  at  all  depths,  and  if  de- 
sired fresh  samples  can  be  taken  as  check  samples  at  any 
time.  Shafts  are  generally  more  expensive  than  drill 
holes,  particularly  those  over  20  feet  in  depth,  conse- 
quently their  number  is  limited  and  this  prevents  a 
thorough  test  of  the  entire  area.  Some  engineers  believe 
that  a  few  shafts  should  be  sunk  even  when  boreholes 
are  used  for  testing  the  majority  of  the  ground  because 
they  will  check  the  boreholes  and  furnish  data  on  the 
kind  of  ground  to  be  worked  later.  In  the  past  there 
has  been  considerable  controversy  as  to  the  relative 
merits  of  shafts  and  drill-holes  when  testing  placers,  but 
after  all  the  drills  have  made  steady  advances  and  are 
adopted  now  almost  universal  when  testing  new  placer 
ground  and  also  in  testing  where  old  placers  are  being 
worked.  When  testing  by  means  of  shafts  two  methods 
of  obtaining  samples  are  available:  one  where  all  the 
material  excavated  is  washed,  and  the  other  where  cuts 
are  made  down  the  sides  of  the  shaft  and  the  material  so 
recovered  is  washed.  In  the  first  case  the  shaft  may  be 
made  any  size  but  some  prefer  to  make  it  2  feet  3  inches 
wide  by  4  feet  long,  the  object  being  to  obtain  one  cubic 
yard  of  dirt  every  three  feet  in  depth.  If  the  shaft  is 
circular  it  may  be  made  3  feet  5  inches  diameter  and  the 
same  amount  of  ground  excavated  every  three  feet  in 
depth. 

Sinking  shafts  of  such  small  size  is  slow  as  the  men  can- 


SHAFT   TESTING  33 

not  work  to  advantage,  especially  where  timbering  is 
needed  to  prevent  the  walls  caving,  and  it  is  for  this 
latter  reason  that  the  rectangular  shaft  is  preferred  to 
the  round  shaft.  The  round  shaft  is  the  better  of  the 
two  forms  when  the  ground  will  stand  because  it  can  be 
dug  quicker  and  kept  in  alignment  better.  For  this 
latter  purpose  a  template  of  two  wooden  cross  pieces, 
about  four  inches  less  in  diameter  than  the  shaft  is  hung 
in  the  center  at  the  top  and  lowered  as  sinking  progresses. 
This  prevents  gouging  the  sides  of  the  shafts  which  is  a 
very  important  matter  where  rich  streaks  are  encoun- 
tered. When  either  kind  of  shaft  reaches  bed  rock  that 
must  be  cleaned  thoroughly  even  if  it  be  necessary  to 
sink  a  foot  or  two  into  bed  rock,  a  condition  which  occurs 
only  when  soft  decomposed  rock  is  encountered.  The 
material  broken  as  sinking  progresses  is  hoisted  from  the 
shaft  in  buckets  usually  raised  and  lowered  by  a  hand 
windlass. 

If  samples  are  from  cuts  in  the  sides  of  the  shaft  their 
cut  widths  should  be  uniform.  One  cut  is  taken  from 
each  end  and  one  from  each  side.  Where  water  is  avail- 
able it  is  believed  that  more  satisfactory  results  would 
be  obtained  from  washing  the  entire  quantity  of  dirt 
excavated,  because  of  the  larger  sample. 

The  difficulties  encountered  in  testing  wet  ground 
when  prospecting  gravel  deposits  led  to  the  introduction 
of  the  well  drill.  The  cost  of  this  method  of  testing  being 
quite  high  and  about  that  of  some  shafts  created  a  de- 
mand for  some  other  kind  of  drilling  arrangement  that 
would  economize  in  cost  particularly  where  the  ground 
to  be  tested  was  not  very  thick.  This  resulted  in  the 


34  GEOLOGY   OF   PLACER   DEPOSITS 

introduction  of  the  Empire  Drill  outfit,  which  is  worked 
by  hand  augmented  in  some  places  by  horse-power. 

The  drill  method  of  testing  placer  ground  consists  in 
forcing  a  pipe  called  a  casing  through  the  deposit  to  bed 
rock.  As  the  casing  descends  the  gravel  in  the  interior 
is  broken  by  a  churn  drill  and  the  small  particles  made 
into  a  sludge  of  a  consistency  that  will  permit  of  their 
being  removed  by  a  pump.  The  sludge  is  washed  to 
recover  the  gold.  If  the  power  drill  is  used  the  casing 
may  be  6  inches  in  diameter,  but  where  the  hand  drill  is 
used  it  is  seldoni  over  four  inches. 

The  area  of  gravel  enclosed  in  casing  pipes  of  this 
diameter  is  very  small  in  comparison  with  an  acre  of 
ground :  for  instance  No.  4  inserted  joint  casing  would  en- 
close an  area  of  .0985  square  foot;  the  No.  5§  casing  (6  in.) 
an  area  of  .  196  square  foot.  Because  of  the  ground  under 
the  cutting  shoe  of  the  casing  being  forced  into  the  hole 
(that  direction  offering  the  least  resistance),  the  area  of 
the  hole  is  increased  by  the  thickness  of  pipe  walls  or  to 
the  outside  diameter  of  the  casing. 

The  No.  4  casing  has  an  outside  diameter  of  4.25 
inches,  the  No.  5!  casing  an  external  diameter  of  6 
inches,  therefore  the  ratio  of  these  pipes  in  area  to  the 
acre  would  be  about  .0000025  part  of  an  acre  for  the 
first  pipe  and  .000005  Part  °f  an  acre  f°r  the  second. 

Another  consideration  to  be  mentioned  in  connection 
with  drill-holes  is  that  the  pump  used  to  clean  the  holes 
sucks  material  from  under  the  end  of  the  pipe  and  values 
taken  for  the  exact  diameter  of  the  pipe  are  considered 
high.  This  was  proved  by  W.  H.  Badford  who  sunk 
a  shaft  3.5  feet  in  diameter  at  Oroville,  California,  us- 


DRILL-HOLE   TESTING  35 

ing  a  drill-hole  in  the  center  of  the  shaft  to  a  depth 
of  34  feet. 

The  gold  obtained  from  the  shaft  corresponded  almost 
exactly  to  the  gold  obtained  from  the  drill-hole  when 
using  a  factor  for  the  latter  of  .27.  This  factor  is  im- 
portant, but  should  be  modified  to  the  diameter  of  the 
casing  pipe.  The  outside  diameter  of  an  outside  coupled 
pipe  is  7.5  inches  and  it  was  with  this  kind  of  pipe  that 
the  test  was  made. 

As  the  area  increases  as  the  squares  of  the  diameters 
the  factor  for  any  pipe  can  be  readily  found  by  the  pro- 
portion, a2  :  b2  ::  .27  :  x.  If  the  gravel  in  an  acre  has 
the  gold  distributed  uniformly  throughout,  the  hole 
would  afford  an  accurate  sample  of  the  deposit;  such 
conditions,  however,  rarely  exist  and  it  is  possible  that 
a  blank  might  be  had  close  to  rich  ground,  or  the  hole 
furnish  the  only  piece  of  gold  in  the  tract. 

It  is  evident  from  this  reasoning  that  placer  ground  in 
new  districts  should  be  drilled  to  find  both  its  probable 
area  and  its  richness  and  while  one  hole  per  acre  might 
do  in  old  river  beds  one  hole  every  200  feet  is  about  the 
area  to  cover  in  unknown  territory. 

The  reliability  of  a  report  on  any  placer  deposit  must 
depend  on  the  care  with  which  the  examination  was  con- 
ducted, consequently  when  a  large  amount  of  capital  is 
involved,  great  risk  is  assumed  in  deciding  to  make  the 
expenditure  on  the  result^of  one  drill  to  an  acre.  To  be 
sure  one  Klondike  estimate  was  based  on  a  1 6-foot  shaft 
and  a  6-foot  drift  for  1000  X  5oo-foot  placer,  and  some 
engineers  have  based  results  making  use  of  one  drill-hole 
to  the  acre;  it  is  believed,  however,  that  more  than  a  few 


GEOLOGY   OF   PLACER   DEPOSITS 


of  the  many  failures  in  hydraulic  mining  have  been  due  to 
insufficient  prospecting. 

In  an  article  on  "Valuing  Dredging  Ground"  by  L.  A. 
Docoto  1  at  least  ten  engineers  took  exception  to  the 
method  which  he  advanced  for  estimating  the  average 
value  of  the  ground. 

Because  of  the  practical  and  theoretical  points  de- 
duced in  the  discussion  Mr.  Docoto's  example  is  used  to 


No.  3 


No.  2 


No.l 


20ft. 

50  c. 

'30  ft. 

No  0( 

25  c. 

30ft. 
No  11< 

12  c. 

25ft. 

35  e. 

20ft. 

No  7l 

160  c. 

25ft. 
No*  r>< 

10  c. 

25ft. 
No  17< 

12  c. 

30ft. 

40  c. 

20  ft. 

20  c. 

35ft. 
Xn    I'll 

10  c. 

32ft. 

130  c. 

20ft. 
No,-6< 

50  c. 

25ft. 
No-l-l-i 

8c. 

30ft. 

N0r-16< 

10  c. 

40ft. 


30ft. 


35ft. 


30ft. 


FIG. 


explain  the  relation  existing  between  the  actual  recovery 
of  gold  from  a  small  area  and  the  whole  area  and  in  cal- 
culating their  values  making  use  of  the  gold  obtained 
from  the  boreholes.  The  plan,  Fig.  5,  is  a  theoretical 
map  covered  by  18  drill  holes  numbered  consecutively. 
The  value  of  gold  from  each  hole  is  marked  on  the  map 
in  cents  per  cubic  yard,  and  below  it  is  marked  the  depth 
of  the  hole  in  feet  to  bed  rock.  To  average  the  gold  per 
1  M.  &  S.  Press,  May,  1914. 


DOCOTO'S   VALUATION   EXAMPLE  37 

cubic  yard  of  gravel  Mr.  Docoto  suggests  that  "  the  gold 
value  from  each  hole  be  multiplied  by  the  depth  of  the 
hole,  that  the  products  be  totaled,  and  that  this  sum  be 
divided  by  the  total  depths  of  the  holes."  The  average 
gold  value  deduced  by  this  method  of  estimation  would, 
unless  a  safety  factor  were  adopted  to  cover  any  probable 
loss,  be  reported  as  37.69  cents  per  cubic  yard.  During 
certain  periods  of  operation  there  will  be  a  recovery  above 
the  average  reported,  while  for  other  periods  there  may  be 
less  than  the  average.  These  special  periods  are  neither 
times  for  rejoicing  nor  gloom  since  they  are  following  out 
the  sequence  of  events  resulting  from  the  ground  being 
richer  in  one  place  than  in  another. 

To  illustrate  the  recovery  from  a  small  area  to  that  of 
the  average  gold  value  of  the  entire  plot,  let  the  lines  join- 
ing the  holes  numbered  i,  3,  8  and  6  enclose  an  area  called 
A ;  then  the  area  bounded  by  the  lines  connecting  holes 

9,  10,  16  and  18  we  will  call  B.    If  the  average  gold  of 
area  A  is  calculated  as  suggested,  it  will  amount  to  72.42 
cents  per  cubic  yard,  while  the  average  gold  of  area  B 
will  figure  as  12.72  cents  per  cubic  yard.    This  shows 
that  neither  the  average  gold  value  of  A  nor  B  can  be 
taken  as  the  standard  by  which  to  judge  the  average 
gold  value  of  the  entire  area  reported  as  37.69  for  the 
entire  placer.    It  also  shows  the  fluctuations  that  occur 
when  an  attempt  is  made  to  average  ground  from  a  few 
holes  far  apart.     In  commenting  on  the  method  it  is  to 
be  understood  that  the  ground  to  be  valued  is  limited 
by  the  lines  connecting  holes  i,  3,  8  and  6,  and  holes  9, 

10,  1 6  and  18,  but  the  entire  area  is  bounded  by  holes  i, 
3,  18,  16  and  i. 


38  GEOLOGY   OF   PLACER   DEPOSITS 

MR.  DOCOTO'S  METHOD  OF   CALCULATING 

Area  A  Area  B 

1.  130  X  40    5200       9.  25  X  25      625 

2.  35  X  30  !°5o  10.  20  X  25  500 

3.  60  X  20  1200  ii.  8  X  35  280 

4.  50  X  20  TOGO  12.  10  X  35  350 

5.  40  X  20  800  13.  15  X  30  45° 
6-  5°  X  30  1500  14.  12  X  25  300 

7.  160  X  20    3200       15.  10  X  30      300 

8.  42  X  3°    J26o       16.  10  X  30      300 

17.  12  X  32      384 
210   15,210      18.  9  X  25      225 

292     3714 

Dividing  15, 210  by  210  gives  an  average  value  of  72.42 
cents  per  cubic  yard  for  Area  A. 

Dividing  3714  by  292  gives  an  average  value  of  12.72 
cents  per  cubic  yard  for  Area  B. 

Considering  the  area  as  a  whole,  18,924  divided  by  502 
gives  37.69  as  the  average  value  in  cents  per  cubic  yard 
of  gravel. 

Since  the  ground  to  be  averaged  is  limited  by  the 
boundary  lines  connecting  the  holes  1,3,  18,  16  and  i, 
the  area  of  the  corner  holes  are  not  representative  of  a 
square  as  Mr.  •Docoto's  example  would  imply,  but  are 
one-quarter  representative  of  an  interior  hole,  say  5  or  7 ; 
further  holes,  2,  8,  13,  12,  6  and  n  are  only  representa- 
tive of  one-half  of  the  area  of  5  and  7.  It  will  be  evident 
from  this  that  Mr.  Docoto's  average  is  too  high  although 
his  average  would  be  correct  for  the  area  given  by  the 
dotted  lines  in  Fig.  6. 

The  method  to  be  followed  in  estimating  the  average 
value  of  placer  ground  is  based  on  the  fundamental 
principle  which  underlies  the  averaging  of  samples, 
namely:  "A  sample  is  supposed  to  represent  the  value 


DIXON'S   METHOD   OF   VALUATION 


39 


of  the  ore,  half  way  between  it  and  the  next  sample ;  with 
terminal  samples,  ore  only  on  one  side  is  taken  into  the 
calculations."  l 

According  to  this  rule  the  results  of  Mr.  Docoto's  tal- 
culations  are  not  weighted  proportionally  to  the  volume 


" 

No.  3 

— 

COc. 

.     r~  n 

|No.8  42  c.  | 

m 

No.l3,15c. 

No.18 

—  1 

9c. 
25ft. 

20ft. 

30ft. 

30ft. 





No.  4.50c<  |  |NO.  9-25c- 

.  

No.14^2  c- 

25ft. 

._. 

No.  2 

35c. 

30ft. 

INO.  ?•      *  

20  ft. 

No,12«^c* 
35ft. 



No.17 

12  c. 
32ft. 

- 



»*«-SSJ  *-»££ 



No.l5.10c- 
30ft. 



- 

No.  1 

L 

130  c. 

50  c. 

8c. 

10  c. 
30ft. 

J 

40ft. 

No.  630ft. 

i  ;          i  i 

No.ll'  35  ft. 



No.16 

FIG.  6. 

of  ground  they  represent.  The  following  method  for 
calculation  of  this  plot  is  advanced  by  James  T.  Dixon 
and  is  based  on  the  rules  given;  at  the  same  time  it  gives 
correctly  the  average  value  and  depth  of  that  portion  of 
the  area  within  the  full  lines  of  Fig.  6.  The  dotted  lines 


Mine  Sampling  and  Valuing,  Herzig,  p.  93. 


40  GEOLOGY   OF  PLACER  DEPOSITS 

represent  the  ground  prospected,  a  value  and  depth  being 
given  in  the  center  of  each  dotted  rectangle. 

The  average  value  is  the  total  value  divided  by  the 
cubical  contents  of  the  ground  in  question,  and  in  order 
to  arrive  at  the  latter  assume  that  the  distance  between 
the  lines  of  holes  is  2  #,  and  that  between  the  holes  2  b. 
By  this  assumption  fractions  will  be  avoided. 

Referring  now  to  hole  No.  i  the  area  to  be  included  in 
the  calculation  is  a  X  &,  the  volume  40  b  and  the  value 
contained  therein  is  5200  ab.  By  similar  calculations 
the  following  results  are  obtained: 

MR.  J.  T.  DIXON'S  METHOD  OF  CALCULATING 


I. 

a 

X 

b 

X 

40 

X 

130 

= 

5,200  ab 

2. 

a 

X 

2b 

X 

30 

X 

35 

= 

2,100  ab 

3- 

a 

X 

b 

X 

20 

X 

60 

= 

1,200  ab 

4. 

2  a 

X 

2b 

X 

20 

X 

5° 

= 

4,000  ab 

5- 

2d 

X 

2b 

X 

20 

X 

40 

= 

3,200  ab 

6. 

2  a 

X 

b 

X 

30 

X 

5° 

m 

3,000  ab 

7- 

2  a 

X 

2b 

X 

20 

X 

1  60 

B 

1  2,  80006 

8. 

2d 

X 

b 

X 

30 

X 

42 

= 

2,52006 

9- 

2  a 

X 

2b 

X 

25 

X 

25 

= 

2,500  ab 

10. 

2  a 

X 

2b 

X 

25 

X 

20 

= 

2,000  ab 

ii. 

2  a 

X 

b 

X 

35 

X 

8 

St 

560  ab 

12. 

2  a 

X 

2b 

X 

35 

X 

10 

= 

1,40006 

13- 

2  a 

X 

b 

X 

30 

X 

15 

= 

900  ab 

14. 

2  a 

X 

2b 

X 

25 

X 

12 

• 

1,200  ab 

15- 

2  a 

X 

2b 

X 

30 

X 

10 

= 

1,200  ab 

16. 

a 

X 

b 

X 

30 

X 

10 

a 

300  ab 

17- 

a 

X 

2b 

X 

32 

X 

12 

= 

768  ab 

18. 

a 

X 

b 

X 

25 

X 

9 

•• 

22506 

Total          m  45,07306 

The  gold  in  the  calculated  volume  is  represented  by 
45,073  ab  and  this  divided  by  48  ab,  the  area  of  the  ground 
in  question,  gives  939.02  as  the  product  of  the  average 
value  and  depth.  To  find  the  average  depth  let  the  line 
A,  Fig.  6,  graphically  represent  the  depth  in  Fig.  7,  which 


DIXON'S    METHOD    OF   VALUATION 


41. 


also  gives  the  boreholes  and  the  distances  between  them. 
The  area  of  this  figure  is 

2  b  (40  +  30)      2b  (30  +  20) 
=  1 20  0. 

2  2 

Because  the  base  has  a  total  length  of  4  b,  the  average 
depth  is  1 20  b  divided  by  46  or  30.    By  similar  calcula- 


40 


30 


FIG.  7. 

tions  the  average  depth  of  each  line  is  found:  Thus 
line  A  =  30;  line  B  =  20;  lineC  =  25;  line  D  =  25; 
line  E  =  33.75;  line  F  =  27.5  and  line  G  =  29.75. 


FIG.  8. 


These  results  may  be  graphically  represented  as  in 
Fig.  8.  Since  this  line  is  at  right  angles  to  the  previous 
ones,  the  distance  between  lines,  namely  2  a,  is  shown 


42  GEOLOGY   OF   PLACER   DEPOSITS 

and  proceeding  as  before  the  total  area  is  found  to  be 
322.25  which  divided  by  12  a  gives  26.854  as  the  average 
depth.  Previously  the  product  of  the  average  depth  and 
average  value  was  found  to  be  939.02  and  this  divided 
by  26.854,  the  average  depth,  gives  34.96  cents  as  the 
average  value  per  cubic  yard.  No  units  are  designated 
in  this  calculation  as  they  make  no  difference  provided 
that  the  same  units  are  used  throughout. 

The  Dixon  method  is  applicable  to  all  cases  whether 
the  lines  or  boreholes  are  spaced  evenly  or  unevenly. 
For  practice  the  reader  may  calculate  the  averages  by 
taking  the  lines  of  boreholes  horizontally  or  diagonally 
instead  of  vertically  as  in  this  calculation.  The  results 
will  be  found  the  same,  which  shows  that  the  method  is 
correct. 

One  feature  brought  out  by  Mr.  Docoto's  theoretical 
problem  was  the  noticeable  fact  that  eight  men  had 
different  ideas  regarding  the  correct  method  to  be  used 
in  arriving  at  the  average  values  of  the  plotted  area,  and 
consequently  obtained  different  results,  some  of  them 
varying  as  much  as  8  cents  per  cubic  yard.  Another 
feature  previously  mentioned  was  that  the  use  of  pris- 
moidal  formulae  failed  to  furnish  the  correct  answer. 

Before  entering  on  the  subject  of  drills  the  method  of 
testing  "  bench  deposits"  is  described. 

In  testing  placer  deposits  by  drifts,  whether  they  are 
advanced  from  the  outside  or  from  the  bottom  of  shafts, 
it  is  advisable  to  wash  the  entire  bulk  of  the  ground 
broken  in  the  drift. 

If  the  deposit  is  deep  and  wide  the  costs  of  prospecting 
by  shafts  at  intervals  is  expensive  and  not  more  reliable 


TESTING   BENCH   DEPOSITS  43 

than  to  drive  headings  each  way  from  the  bottom  of  a 
shaft  towards  rim-rocks. 

It  is  advisable  to  drive  the  headings  on  bed  rock,  in  a 
direction  that  will  be  at  right  angles  to  the  flow,  to  reach 
the  rim-rocks  by  the  shortest  distance,  also  to  obtain 
more  accurate  values  than  would  be  the  case  where  the 
excavations  were  made  at  an  angle  more  or  less  parallel 
to  the  channel.  In  driving  drifts  of  this  kind  it  is  neces- 
sary that  the  ribs  or  side  walls  of  the  excavation  be  kept 
straight  and  of  uniform  width,  as  gouging  would  probably 
increase  the  values  from  the  pay  streaks  and  decrease 
them  if  barren  ground  is  gouged.  In  drifts  of  this  kind 
it  is  customary  to  base  the  value  of  gold  obtained  on  the 
number  of  square  yards  of  bed  rock  uncovered,  then  from 
this  datum  and  the  thickness  of  the  gravel  above  bed  rock 
along  the  line  of  the  drift  the  value  per  cubic  yard  is 
computed.  As  an  illustration:  Assume  that  the  deposit 
increases  in  depth  uniformly  from  rim-rocks  to  the  center 
of  the  channel,  and  that  all  the  gold  is  deposited  in  a 
stratum  or  bench  on  bed  rock,  having  from  18  to  24  inches 
thickness.  To  test  this  deposit  assume  a  shaft  is  sunk 
39  feet  to  bed  rock  and  that  by  drifting  at  right  angles 
to  the  channel  the  width  of  the  deposit  was  found  to  be 
72  feet.  The  area  of  the  excavation  was  made  5X6 
feet  for  convenience  in  working,  and  the  width  was  kept 
uniformly  5  feet,  until  the  ribs  reached  the  height  of  4 
feet  9  inches  when  the  roof  was  arched,  or  if  weak  was 
supported  by  timber  sets,  and  lagging. 

When  driving,  all  dirt  was  wheeled  in  barrows  to  the 
bottom  of  the  shaft  and  hoisted  to  the  surface,  where  it 
was  washed  in  sluice  boxes,  the  gold  being  caught  in 


44 


GEOLOGY   OF   PLACER   DEPOSITS 


riffles.  By  drifting  $181.38  in  gold  was  obtained  from 
72X  5-5-9  =  40  square  yards  of  bed  rock  uncovered; 
thus  the  yield  was  $4.53  per  square  yard.  By  surveying 
along  the  line  of  the  drift  the  average  depth  of  the  cover 
was  found  to  be  33.3  feet  or  n.i  yards.  Dividing  the 
value  per  square  yard  of  bed  rock  by  this  depth  in  yards 
the  value  of  the  assumed  deposit  is  found  to  be  40.8  cents 
per  cubic  yard. 


FIG.  9. 

Prospecting  with  Drills.  —  It  is  now  generally  con- 
ceded that  placer  prospecting  may  be  accomplished  with 
great  saving  in  time  and  fairly  accurately  by  the  use  of 
percussion  drills.  The  Keystone  Drill  rig  shown  in 


PROSPECTING   WITH   DRILLS  45 

Fig.  9  is  a  portable  well  drilling  rig  that  has  found  favor 
in  many  countries.  With  this  power  drill  the  earth  in 
the  bottom  of  the  hole  is  broken  in  advance  of  the  casing 
pipe  which  follows.  As  soon  as  the  casing  reaches  the 
bottom  of  the  hole,  water  is  poured  in  and  a  sludge  formed 
of  such  consistency  that  it  may  be  drawn  out  by  a  pump. 
It  may  be  necessary  to  have  water  in  the  bottom  of  the 
hole  at  all  times,  especially  when  drilling  rock;  then 
again  water  may  naturally  be  present;  however,  before 
the  pump  is  used  the  casing  should  be  at  the  same  depth 
as  the  bottom  of  the  hole,  otherwise  it  may  be  enlarged 
by  the  action  of  the  pump. 

The  muck  raised  from  the  hole  is  poured  from  the 
pump  directly  into  a  washer  and  the  gold  recovered. 

In  recent  years  the  Empire  Drill  has  found  favor 
among  engineers.  It  consists  of  a  combination  of  ar- 
rangements obtained  by  assembling  the  ancient  post-hole 
augur  with  the  churn  drill,  and  such  other  advantages 
as  well  drills  possessed;  at  the  same  time  there  is  original 
invention  displayed  which  places  it  in  a  class  by  itself. 

The  outfit  consists  of  a  pipe  or  casing  supplied  at  one 
end  with  a  sharp-toothed  cutting  shoe,  which  is  kept 
loose  in  the  hole  by  rotation  and  in  this  way  sinks  evenly 
with  the  bit  of  the  drill. 

To  this  pipe,  at  suitable  distance  above  the  ground,  an 
iron  platform  is  fastened  as  shown  in  Fig.  10.  On  this 
platform  men  stand  to  raise  and  lower  a  drill  which  is 
inside  the  pipe.  The  drill  consists  of  a  series  of  rods 
having  a  bit  at  the  lower  end  with  a  grip  handle  at  the 
upper  end  for  the  purpose  of  raising  the  rods  and  letting 
them  drop  about  i  foot. 


46  GEOLOGY   OF   PLACER  DEPOSITS 

In  all  percussive  drilling  water  is  required  for  making 
sludge  at  the  bottom  of  the  hole  in  order  that  the  ma- 
terials may  be  removed  and  permit  the  drill  to  cut  the 
rock.  The  sludge  pump  is  a  working  barrel  with  a  flap 


valve  in  the  bottom  which  opens  inwards  as  it  descends 
and  downwards  as  it  ascends.  Sometimes  this  pump 
works  slowly  and  so  fails  to  clean  the  hole  as  much  as 
desired,  therefore  the  vacuum  sludge  pump  is  finding 
favor.  This  consists  of  a  working  barrel  as  before  with  a 
foot  valve,  but  in  addition  it  has  a  piston  valve  on  a  rod 
which  on  being  moved  upwards  causes  a  vacuum  and 
draws  the  sludge  into  the  barrel.  The  method  of  work- 
ing the  drill  is  as  follows: 


PROSPECTING   WITH   DRILLS  47 

The  casing  is  started  by  boring  a  hole  with  a  post 
augur  to  a  depth  that  will  insure  the  former  remaining 
vertical.  After  insertion  in  this  hole  the  casing  is  rotated 
by  a  sweep  pushed  by  men  or  animals,  thus  cutting  a  core 
in  the  ground  from  the  surface  to  bed  rock.  To  sink  the 
casing  and  afford  grip  to  its  cutting  bit,  there  is  the  com- 
bined weight  of  the  platform,  the  drillers,  the  drill  rods 
and  the  casing.  This  combined  weight  is  always  suffi- 
cient to  sink  the  casing  when  rotated  and  kept  loose  in  the 
hole.  Although  a  core  is  marked  out  by  the  casing, 
nevertheless  most  of  the  drilling  is  done  by  the  tools 
inside  the  casing  being  churned  up  and  down  by  the 
drillers. 

One  of  the  recent  improvements  to  the  Empire  rig  is 
the  use  of  a  hollow  drill  stem  attached  to  the  bottom  of  a 
sand  pump  which  in  turn  is  fastened  to  the  drill  rods. 
This  combination  picks  up  the  drill  clippings  as  fast  as 
cut,  provided  sufficient  water  is  kept  in  the  hole  to  form 
a  fluid  sludge.  The  advantages  claimed  for  this  com- 
bination are:  the  casing  is  sunk  and  the  material  re- 
moved out  of  the  way  of  the  bit  at  the  same  time,  thus 
doing  away  with  three  operations  which  other  drills 
require  to  accomplish  the  same  advance;  viz.,  raising 
and  uncoupling  the  drill  rods  every  time  the  hole  has  to 
be  cleaned  out,  using  the  pump,  lowering  the  drill  rods 
after  sludging.  When  boulders  or  other  obstacles  are  en- 
countered which  interfere  with  sinking,  a  heavy  fluted 
rock  drill  is  attached  to  the  rods  and  the  sand  pump 
mentioned  is  removed  from  the  sinking  rods  and  a  solid 
string  of  tools  thus  obtained.  The  combined  action  of 
the  casing  and  drill  are  such  that  the  obstacle  is  readily 


48  GEOLOGY   OF   PLACER   DEPOSITS 

passed  through,  although  it  may  be  possible  to  shatter 
the  rock  in  the  bottom  of  the  hole  with  dynamite  and  thus 
hasten  the  process.  When  a  hole  is  completed  to  bed- 
rock, the  casing  is  pulled  by  suitable  tools  and  reused 
for  putting  down  another  hole.  The  weight  of  the  ap- 
paratus without  casing  is  1000  pounds;  however,  as  no  one 
piece  weighs  more  than  75  pounds,  it  is  considered  port- 
able. The  weight  of  the  complete  outfit  with  4-inch\ 
casing  and  necessary  drill  rods  to  drill  to  a  depth  of  25 
feet  is  2000  pounds;  to  drill  to  a  depth  of  50  feet,  2500 
pounds.  For  greater  depths  the  weight  of  the  outfit 
increases  at  the  rate  of  20  pounds  to  the  foot;  thus  to 
drill  to  a  depth  of  100  feet  the  weight  would  be  75  X  20 
+  2000  =  3500  pounds. 

J.  P.  Hutchins  and  N.  C.  S tines  furnished  cost  data 
based  on  their  work  with  this  drill  rig.  The  late  Fritz 
Circle  who  made  use  of  it  in  Canada  recommended  the 
drill  and  his  account  will  be  found  in  one  of  the  Canadian 
Bureau  of  Mines  Reports. 

"  With  labor  at  $i  per  day  and  a  horse  at  $i  per  day, 
with  ground  from  30  to  50  feet  deep,  the  actual  drilling 
costs  from  12  to  30  cents  per  foot.  In  frozen  ground  25 
feet  deep  in  which  2  feet  per  hour  may  be  averaged  the 
cost  is  23  cents  per  foot.  In  Idaho,  with  labor  at  $3.50 
per  shift  and  working  under  the  disadvantages  of  deep 
snow  and  very  cold  weather,  37!  feet  were  drilled  in  8^ 
hours  at  a  cost  of  65  cents  per  foot.  Under  more  favor- 
able conditions  in  Colorado,  with  labor  at  $2.50  per  day, 
the  progress  was  42  feet  per  day  and  the  cost  27  cents 
per  foot.  Where  labor  was  20  cents  per  hour  and  the 
gravel  18  feet  thick  five  men  and  one  horse  averaged  51 


PROSPECTING   WITH   DRILLS  49 

feet  per  day  at  a  cost  of  23  cents  per  foot."  Among  the 
advantages  to  be  considered  when  making  use  of  this 
outfit  is  its  portability;  thus  the  holes  for  the  casing  may 
be  started  in  advance  of  actual  drilling,  or  on  account  of 
its  light  weight  several  drills  may  be  worked  over  the 
ground  to  be  tested  at  the  same  time.  In  comparison 
with  the  steam  power  drill  the  cost  of  the  outfit  is  less  and 
it  can  be  used  where  the  steam  drill  would  be  impossible. 

Where  holes  are  to  be  more  than  25  feet  deep  it  is 
possible  to  effect  a  saving  in  operating  costs  by  adopting 
the  Empire  spring  drilling  attachment.  The  action  of 
this  apparatus  is  similar  to  the  spring  pole  and  has  the 
added  advantage  of  assisting  in  raising  and  lowering  the 
drill  rods  when  they  must  be  drawn  from  the  hole.  The 
attachment  consists  of  a  small  drum  geared  to  a  crank 
and  shaft.  There  is  a  brake  attachment  to  the  drum 
which  enables  the  operator  to  drop  the  tools  at  will. 

The  spring  is  also  attached  to  the  drum  shaft,  and  when 
given  tension  sufficient  to  counterbalance  a  string  of 
tools,  it  aids  the  drillers  greatly  in  raising  them  just  be- 
fore letting  them  drop.  This  is  accomplished  by  attach- 
ing a  rope  to  the  drum,  and  to  the  string  of  tools  at  some 
distance  below  the  surface  in  the  hole.  With  this  at- 
tachment two  men  have  drilled  to  a  depth  of  125  feet. 


CHAPTER  II. 

HYDRAULIC   MINING. 

HYDRAULIC  MINING  was  once  defined  as  a  method  of 
mining  in  which  water  broke  down  gold-bearing  earth, 
transported  it  to  sluices,  and  separated  the  gold  from 
the  earth. 

The  definition  is  not  sufficiently  broad,  as  hydraulic 
mining  when  applied  to  gold-bearing  earths  not  only 
breaks  and  transports,  but  washes  the  material  and  per- 
mits the  gold  to  separate  by  its  greater  specific  gravity. 
It  is  also  a  concentrating  and  sluicing  process.  The 
process  of  mining  and  transporting  by  water  can  be 
applied  to  coal,  iron  ore,  salt  and  possibly  other  minerals, 
for  which  reason,  the  term  hydraulic  mining  should 
not  be  confined  to  gold  alone.  In  view  of  the  scope 
that  the  term  covers,  the  suggestive  term  "  hydraulick- 
ing"  is  applied  to  gold  mining,  and  the  term  hydraulic 
mining  used  to  cover  all  materials  mined  by  the  use  of 
water. 

Hydraulic  mining  frequently  requires  the  services  of 
civil,  hydraulic,  mechanical  and  mining  engineers  to 
install  a  plant,  or  at  least  an  engineer  who  is  able  to 
combine  those  branches  of  the  professions  mentioned  that 
enter  into  the  business. 

Before  any  attempt  is  made  at  engineering  the  gold- 
bearing  ground  should  be  prospected  carefully,  in  order 
to  ascertain  its  extent  and  value.  Several  million 

50 


ANCIENT  MINING  51 

dollars  have  been  expended  in  overcoming  difficult 
engineering  problems  to  wash  dirt  that  did  not  contain 
sufficient  gold  to  pay  the  cost  of  the  plant,  which  fact 
emphasizes  the  need  of  thorough  prospecting. 

The  value  of  the  property  having  been  determined, 
it  may  be  necessary  in  order  to  work  it  successfully  to 
construct  dams  for  storage  reservoirs,  and  a  combina- 
tion of  flumes,  ditches,  and  pipe  lines,  extending  from 
one  to  one  hundred  miles  in  length,  and  in  addition  it 
may  be  necessary  to  tunnel  mountains,  span  chasms, 
siphon  across  valleys,  place  flumes  on  high  trestles  or 
suspension  bridges,  and  possibly  bracket  them  to  the  sides 
of  high  cliffs.  From  what  has  been  stated  the  reader 
will  understand  that  hydraulic  mining  may  in  one  case 
be  simple  while  in  another  it  may  be  intricate  and 
difficult. 

It  is  only  possible  to  describe  many  matters  entering 
into  the  subject  in  a  general  way,  while  the  most  impor- 
tant are  described  in  detail. 

The  use  of  water  for  mining  dates  back  to  King 
Solomon's  time.  Agricola  informs  us  that  fire  was  used 
to  heat  the  rocks,  and  then  cold  water  was  thrown  on  them 
to  spall  them.1 

In  quarrying  where  seams  exist  in  bedded  rock,  and 
where  explosives  would  be  apt  to  shatter  the  rock  being 
quarried,  water  is  employed  with  wood. 

1  While  recently  in  Cuba,  the  author  heard  that  Cubans  used  to  mine 
an  ore,  bum  it  and  then  wash  it  in  pans.  Upon  investigation  a  calcite 
vein  containing  gold  was  found,  and  since  the  Cubans  had  no  machinery 
this  method  answered  their  purpose.  A  little  of  the  ore  was  treated 
this  way  and  gave  good  results,  showing  that  the  ancients  were  not  so 
slow  where  gold  was  concerned. 


52  HYDRAULIC  MINING 

The  method  followed  is  to  drill  a  series  of  holes  back 
from  but  parallel  to  the  face,  on  the  line  of  cleavage. 
Into  these  holes  dry  wooden  wedges  are  driven.  These 
wedges,  on  being  wet,  expand  and  split  the  rock  as 
desired.  The  plug  and  feather  generally  in  use  in  such 
cases  does  not  always  answer  as  well  as  the  wedges 
mentioned. 

The  danger  which  arises  from  the  use  of  gunpowder 
in  gaseous  coal  mines  has  produced  two  classes  of 
expansive  cartridges  which  depend  upon  water  for  their 
utility.  The  coal  is  undercut  in  the  usual  manner,  and 
holes  drilled  in  the  section  to  be  broken  down. 

1.  Into    these    drill-holes    cartridges   of    compressed 
quicklime  are  inserted,  after  which  they  are  moistened, 
then   tamped.     The   water   used   to   moisten   the   lime 
causes  it  to  slack,   expand,   and   generate  steam;  this 
combination   breaks   down   the   coal.     The   economical 
value  of  this  novelty  has  not  been  fully  established  in 
this    country.     The    number    of   drill-holes    and    lime 
cartridges  would  possibly  bring  the  cost  of  the  process 
up  to  that  of  powder;  however,  the  smaller  undercut, 
and  the  reduction  in  the  amount  of  slack  coal  produced, 
compared   with  powder,   may  counterbalance   previous 
objections.     The  distinctive  advantage  which  this  process 
possesses  is  the  avoidance  of  explosion  in  mines  which 
are  subject  to  outbursts  of  gas. 

2.  The   water  cartridge  of   the  second    type  is   also 
intended  for  use  in  fiery  coal  mines. 

It  is  a  metal  wedge,  so  contrived  that  upon  the  appli- 
cation of  hydraulic  pressure  it  will  expand. 
To  break  down  the  coal  a  series  of  wedges  are  con- 


SALT  MINING  53 

nected,  so  that  when  the  pressure  is  applied  it  is  uniform 
on  all.  The  cartridges  being  indestructible  may  be 
used  over  again.  They  have  not  come  into  general 
use  in  this  country.  Cartridges  of  this  description,  if 
they  could  be  used  from  water  pressure  at  the  mouth 
of  some  metal  mines  in  the  West,  would  be  a  great  bless- 
ing, in  preventing  the  fouling  of  air  and  loss  of  life, 
not  to  mention  economy  in  the  matter  of  powder,  time, 
and  fuse.  Their  use  would  be  limited  to  overstepping. 

Salt  mining  uses  water  in  practical  ways  as  follows: 

i.  As  a  solvent.  For  this  purpose  a  series  of  bore- 
holes are  drilled  from  the  surface  down  into  the  deposit 
by  percussion  or  diamond  drills. 

Water  is  then  run  into  the  holes  and  allowed  to  become 
saturated  with  salt,  after  which  the  brine  is  pumped 
out  and  more  fresh  water  added. 

By  a  series  of  these  bore-holes  near  together  an  under- 
ground water  course  which  connects  the  holes  is  soon 
formed  in  the  salt  bed.  Nitroglycerine  fired  in  the 
holes  will  shatter  the  rock  and  is  useful  in  hastening 
the  connection.  The  water,  after  circulation  is  estab- 
lished, flows  continuously  from  the  surface  into  one  hole, 
and  is  pumped  out  at  the  same  rate  it  enters  from  an- 
other hole.  The  working  is  now  permanent,  one  bore- 
hole supplies  the  water,  and  another  is  fitted  with  a 
deep  well-pump  to  remove  the  brine. 

This  method  has  advantages,  in  some  instances,  over 
any  other  method  of  mining  salt  where  the  material  is 
to  be  broken  down,  hoisted,  dissolved,  and  then  con- 
centrated. It  also  offers  the  further  advantage  of  leav- 
ing the  impurities  in  the  mine,  and  brings  the  article 


54 


HYDRAULIC  MINING 


sought  in  the  proper  concentrated  form  for  refining  to 
the  vats. 

2.  The  hydraulic  mining  termed  "  spatterwork "  origi- 
nated in  the  salt  mines  of  Europe,  where  it  has  received 
considerable  attention.  The  water  used  for  mining  is 
given  a  gravity  pressure  and  ejected  from  a  nozzle  having 
a  number  of  small  orifices.  The  water  from  this  nozzle 
strikes  against  the  salt  deposit  and  wears  it  away;  at  the 
same  time,  in  flowing  away  it  dissolves  the  salt,  leaving 
the  worthless  debris  to  be  broken  down  or  removed. 
The  brine  is  then  collected  by  gravity  in  sumps  or  sub- 
terranean reservoirs,  from  which  it  is  pumped  to  the 
surface  and  evaporated. 

Spatterwork  can  be  employed  in  salt  deposits  for 
sinking  shafts  and  winzes  -from  a  higher  to  a  lower 
level,  or  making  "rises"  from  a  lower  to  a  higher  level. 


FIG.  ii. 

Gangways  or  rooms  may  be  driven  in  salt  deposits  by 
the  method  crudely  shown  in  Fig.  n.  For  side  cutting, 
the  main  supply  pipe  for  water  has  coupled  to  it,  by  a 
hose,  a  standpipe,  SP.  This  pipe  is  wedged  between 
the  roof  and  floor,  in  an  upright  position,  with  the  ori- 
fices directed  toward  the  face.  The  water  jets  wear 


SPATTERWORK 


55 


away  the  deposit  by  solution  and  abrasion,  and  the 
deposit  recedes  from  the  orifices  of  the  water  jets  until 
the  projective  force  of  the  water  has  reached  its  limit. 
The  water  is  then  turned  off  and  the  column  pipe 
placed  in  another  position,  where  the  water  by  its  pro- 
jective force,  together  with  its  solving  action,  can  per- 
form more  effective  work. 

The  same  illustration  shows  the  method  of  under- 
cutting the  deposit  of  saliferous  clay.  The  spatter  pipe 
is  placed  upon  the  floor  and  is  moved  forward  to  deepen 
the  excavation,  or  laterally  to  widen  it.  The  undercut 
having  been  made,  the  clay  is  easily  wedged  down 


SP 


FIG.  12. 


FIG.  13. 


where  it  may  be  acted  upon  by  a  stream  of  water  which 
takes  the  salt  into  solution  and  leaves  the  barren  dirt. 
The  quantity  of  water  is  limited  to  the  capacity  of  the 
pumps  and  that  necessary  for  saturation  of  the  brine. 
Water  may,  in  some  instances,  be  used  on  one  level 
and  be  permitted  to  flow  to  the  next  lower  level,  and 


56  HYDRAULIC   MINING 

so  on,   thus  attaining  the  requisite  saturation  before 
reaching  the  pumps  and  sumps. 

Wherever  the  latter  conditions  prevail,  winzes  or  risers 
may  be  made  as  roughly  sketched  in  Figs.  12  and  13. 

To  sink  the  winze,  it  is  necessary  to  drill  a  bore-hole 
from  the  level  above  to  the  level  below,  to  allow  the 
escape  of  the  water  discharged  from  the  nozzle  N.  The 
water  from  the  supply  pipe  on  the  upper  level  acts  by 
gravity,  and  propels  the  water  from  the  jet  holes  in  the 
nozzle  against  the  sides  of  the  shaft.  It  is  evident  in 
this  instance  that  the  action  of  the  water  increases  its 
projective  force  with  depth  until  it  reaches  its  maximum 
when  the  lower  level  is  reached.  Fig.  13  shows  the 
method  of  working  out  a  "rise."  To  facilitate  this 
latter  method,  water  is  brought  under  pressure  greater 
than  the  height  to  be  driven,  as  it  decreases  in  projective 
force  with  height. 

Mr.  Oswald  J.  Heinrich  stated  that  with  a  21 -foot 
head  of  water,  and  side  cutting  from  a  spatter 
pipe  having  twelve  brass  orifices  \  mm.  diameter, 
the  advance  was  0.6  square  feet  per  minute,  with 
i  cubic  foot  of  water  per  minute.  One  man  attends  to 
12  spatter  pipes  in  a  1 2-hour  shift.  This  rate  of  exca- 
vation is  in  round  numbers  5184  cubic  feet  per  day, 
with  8640  cubic  feet  of  water  and  one  man's  labor,  thus 
comparing  favorably  with  any  hydraulic  mining,  as  it 
is  .052  cents  per  cubic  yard  for  labor,  and  not  as  high 
in  amount  for  water  as  gravel  mining  generally. 

Iron  ore  deposits  of  an  alluvial  character,  such  as 
are  the  " brown  ore"  deposits  of  Virginia,  can  be  worked 
to  great  advantage  by  "  hydraulicking "  if  situated  on 


IRON   ORE   MINING  57 

side  hills.  In  such  instances  the  ore  is  disseminated 
through  clay  with  barren  rocks  in  such  a  manner  as  to 
need  both  concentration  and  washing.  It  may  be  ne- 
cessary to  wash  ten  tons  of  material  to  concentrate  one 
ton  of  ore.  The  cost  of  excavating  and  handling  such 
lean  iron  oxide  deposits  would  make  the  bed  commer- 
cially unprofitable,  if  freight  must  be  added ;  it  has,  how- 
ever, been  practically  demonstrated  to  be  more  econo- 
mical to  burn  fuel  and  pump  water  uphill  and  hydraulic 
than  to  work  by  the  former  method.  To  illustrate  this 
more  fully :  to  pick,  shovel,  and  transport  the  material  to 
the  washer,  wash  it,  and  load  it  on  cars,  will  cost,  for  10 
tons,  $2.00  —  i.e.,  one  ton  of  iron  ore. 

To  accomplish  the  same  work  with  water  having  a 
head  of  50  feet  will  cost  75  cents  per  ton  of  iron  ore. 
The  hydraulic  system  materially  lessens  the  work 
to  be  done  by  the  washer,  as  the  ore  becomes  freed 
in  a  measure  from  clay  as  it  travels  through  the  sluices 
to  the  washer. 

There  is  one  more  system  of  water  mining  made  men- 
tion of  by  Pliny  in  his  "Natural  History."  It  has  been 
practiced  somewhat  in  this  country,  and  is  termed 
"booming." 

The  process  of  "booming"  is  to  make  a  dam  and 
collect  water;  whenever  the  dam  is  full  the  gates  are 
opened  quickly,  allowing  a  torrent  of  water  to  rush 
down  the  hill  and  upset  matters  generally.  The  water, 
having  done  its  work,  is  led  through  sluices  which  are 
nearly  on  a  level  at  the  foot  of  the  hill;  in  these  sluices 
the  gold  washed  out  of  the  soil  is  collected. 

Booming  has  some  advantages  which  are  not  to  be 


58  HYDRAULIC  MINING 

overlooked.  If  there  is  little  water  and  little  working 
capital  the  method  will  be  found  very  serviceable,  or 
if  there  is  considerable  water  and  little  working  capital 
it  again  appeals  to  the  miner.  In  some  cases  where 
there  is  abundance  of  capital  the  method  is  adopted  as 
the  one  most  feasible  for  placer  mining. 

Booming  will  wash  out  a  large  quantity  of  material, 
and  in  its  operation  is  an  imitation  of  a  cloud-burst 
rushing  down  a  ravine.  Where  there  is  top  dirt  above 
a  placer,  booming  affords  a  quick  and  easy  method  of 
removing  it,  provided  the  dirt  is  not  hardpan  and 
cemented  gravel. 

Float  gold  and  leaf  gold  cannot  be  saved  if  booming 
is  practiced,  and  only  partially  saved  by  other  hydraulic 
methods. 

In  Colorado  at  the  Alma  and  Fairplay  placers  a  sys- 
tem of  hydraulic  mining  termed  " ditch  waterfall"  and 
" flume  waterfall"  mining  is  practiced.  At  these  places 
there  is  plenty  of  water,  and  this  flowing  through  ditches 
wears  away  the  earth.  The  water  in  the  ditch  naturally 
cuts  its  own  channel,  thus  forming  narrow  ravines  and 
gashes  in  the  deposit  that  are  useful  in  assisting  the  water 
spurted  from  nozzles  in  tearing  down  the  bank.  By 
shifting  these  ditches  or  by  turning  the  water  into  other 
ditches,  considerable  space  may  be  covered  and  the  earth 
washed  down  to  the  sluice  boxes  without  any  cost  of 
attendance. 

This  method  combined  with  the  pipe  work  practiced 
at  these  places  forms  the  most  satisfactory  system  of 
hydraulicking.  Unfortunately,  however,  it  cannot  be 
followed  at  every  placer  mine. 


CULM   PILE   MINING 


59 


In  the  early  days  of  anthracite  mining,  great  difficulty 
was  experienced  in  the  preparation  of  coal  for  market. 
All  bone  coal,  or  coal  frozen  to  slate  or  rock,  was  thrown 
on  the  rock  pile;  and  in  addition  all  coal  smaller  than 
chestnut  size,  that  passes  over  a  screen  with  f-inch 
mesh,  but  through  a  screen  having  a  mesh  if  inches 
square,  was  discarded.  This  waste  accumulated  so 


FIG.  14. 

fast  that  the  culm  piles  throughout  the  three  anthracite 
felds  became  veritable  mountains.  With  the  increased 
demand  for  coal,  the  attention  of  coal  operators  was 
given  to  preparing  smaller  sizes  than  chestnut  for 
steam  purposes.  In  1867  pea  coal  was  first  utilized 
for  fuel;  in  1878  buckwheat  was  shipped  on  a  small 
scale,  but  as  soon  as  McClave's  rocking  grate  and  the 
Wooton  or  camelback  locomotive  were  introduced  the 
demand  increased  rapidly,  until  at  the  present  time 


60  HYDRAULIC  MINING 

No.  3  buckwheat  or  barley  size  is  prepared  and  shipped 
in  large  quantities.  When  the  demand  for  small  sizes 
became  greater  than  the  mines  could  produce,  attention 
was  turned  to  the  utilization  of  the  culm  piles.  These 
are  mined  by  water;  in  fact,  hydraulic  mining  is  now 
carried  on  to  a  larger  extent  for  mining  coal  in  north- 
eastern Pennsylvania  than  for  mining  all  the  other 
minerals  in  the  United  States.  The  stream  of  water 
from  a  nozzle  washes  down  the  coal  into  a  sheet  iron 
trough  placed  at  a  slight  inclination.  The  trough  con- 
nects with  the  washery  where  the  coal  is  prepared  for 
market,  or  with  a  swinging  scraper  line  such  as  that 
shown  in  Fig.  14  leading  to  the  washery.1 

Dredging  for  coal  in  the  Susquehanna  River  is  also 
carried  on  from  Wilkes  Barre  to  Sunbury,  Pennsylvania. 
The  coal  found  in  the  river  has  been  transported  from 
the  waste  dumps  at  the  collieries  and  from  the  washeries 
adjacent  in  the  river. 

1  M.  and  M.,  1903,  June.     A.  I.  M.  E.,  Nov.,  1905.     George  Harris. 


CHAPTER  III. 

DEVELOPMENT   OF  PLACER  MINING. 

IN  the  early  days  the  ancients  depended  on  placers 
for  their  supply  of  gold.  As  they  had  practically  no 
machinery  suitable  for  quartz  mining,  it  may  be  assumed 
that  the  Egyptians  previous  to  Herod's  time  practiced 
some  form  of  hydraulic  mining.  The  Romans  sluiced 
for  gold,  and  according  to  Pliny  the  shores  of  Spain 
were  added  to  by  booming.  One  English  writer  states 
that  nine-tenths  of  all  the  gold  has  been  recovered  by 
hydraulic  methods,  while  an  American  writer  declares 
that  over  seventy- five  per  cent  of  all  the  gold  mined  has 
been  derived  from  working  gravel  beds.  Probably  five- 
tenths  of  all  the  gold  recovered  at  a  profit  has  been 
taken  from  placers.  While  placers  are  not  as  rich 
ordinarily  as  veins,  and  while  they  cover  vastly  greater 
areas  than  vein  formations,  nevertheless  the  gold  is 
more  easily  recovered  from  them.  This  is  due  to 
Nature's  pulverizing  the  rocks  and  concentrating  the  gold, 
thereby  doing  away  with  underground  mining,  crushing, 
milling,  or  smelting,  items  which  add  so  materially  to 
the  cost  of  production  that  vein  mining  frequently  pays 
only  expenses,  and  more  frequently  shows  a  debit  balance 
on  the  ledger. 

The  pan,  cradle,  and  sluice  were  first  introduced  in 
the  Southern  States  before  gold  was  discovered  in  Cali- 

61 


62  DEVELOPMENT  OF  PLACER  MINING 

fornia,  but  hydraulicking  as  now  practiced  was  devel- 
oped in  California. 

Panning.  —  The  ordinary  gold  pan  of  the  prospector, 
while  very  useful  is  an  imperfect  appliance  in  which 
to  save  fine  gold.  While  colors  of  gold  may  be  de- 
tected by  the  pan,  it  is  very  difficult  to  collect  them 
free  from  black  sand,  consequently  the  pan  is  useful  to 
placer  miners  only  for  nugget  gold,  unless  they  use 
mercury,  and  this  they  seldom  do.  In  tracing  up  gold 
deposits  the  pan  has  no  equal,  particularly  deposits 
that  show  free  gold.  The  Spaniards  introduced  the 
batea  or  wooden  pan  into  Mexico,  where  they  are 
still  found  to  some  extent,  when  sheet  iron  pans  are 
not  available.  The  most  expert  panner  the  writer  has 
ever  seen  was  a  Mexican  Indian  who  used  a  small 
lo-inch  frying-pan  with  the  handle  knocked  off. 

The  ordinary  sheet  iron  gold  pan,  from  16  to  18 
inches  in  diameter,  will  hold  from  15  to  25  pounds  of 
dirt,  and  with  its  load  will  require  the  use  of  both  hands 
during  washing  operations.  A  smaller  pan  10  inches 
across  the  top  will  hold  from  3  to  5  pounds  of  dirt  and 
can  be  manipulated  with  comparative  ease,  and  is, 
therefore,  better  for  prospecting. 

A  good  placer  miner,  by  washing  continuously  ten 
hours,  can  pan  from  one-half  a  cubic  yard  to  one  cubic 
yard  of  dirt,  depending  of  course  on  the  character  of 
the  dirt  and  his  nearness  to  water.  If  the  ground  is 
loose  and  contains  stones  of  the  size  of  one's  fist,  more 
can  be  washed  than  when  the  ground  is  fine  or  is  cemented 
material.  Ordinary  gravel,  as  found  in  placers,  will 
probably  average  135  pounds  per  cubic  foot;  at  this 


GOLD   PANNING  63 

figure  27  cubic  feet  would  weigh  3645  pounds.  Assum- 
ing that  each  pan  washed  contained  15  pounds,  then  it 
would  require  243  pans  to  wash  a  cubic  yard. 

A  good  days  work  for  a  placer  miner  under  medium 
conditions  is  100  pans  of  dirt  in  10  hours.  It  is  difficult 
to  describe  the  motion  given  to  a  gold  pan  when  washing 


FIG.  15. 

dirt;  the  object,  however,  is  to  separate  the  gold  from 
the  material  with  which  it  is  associated.  The  placer 
dirt  is  shoveled  into  the  pan  until  it  is  heaping  full.  The 
pan  and  its  contents  are  then  submerged  in  water,  to 
loosen  the  material.  The  large  stones  are  washed  first 
to  remove  any  adhering  dirt  that  may  contain  gold, 
after  which  they  are  thrown  away.  The  contents  of 
the  pan  are  then  kneaded  with  both  hands,  to  break  up 


64  DEVELOPMENT  OF  PLACER  MINING 

clay,  and  float  the  mud  away.  When  there  is  nothing 
but  sand  and  gravel  in  the  pan,  the  panning  operation 
commences  and  is  continued  until  only  the  heavier 
particles  remain.  If  a  little  clear  water  is  now  added 
the  gold  in  the  bottom  of  the  pan  will  show.  In  most 
cases  only  the  gold  is  saved;  however,  the  black  sands 
may  be  so  valuable  it  will  pay  to  save  them,  particularly 
if  there  is  flour  gold. 

Gold  frozen  to  quartz  is  frequently  found  when  pan- 
ning. This  rock  should  be  pulverized  and  treated  as 
in  pan  assaying.  The  pan  for  this  purpose  should  be 
black,  of  Russian  sheet-iron,  and  of 
the  shape  shown  in  Fig.  16. 

The  pan  is  held  firmly  by  one 
hand,  some  water  is  then  poured  on 
the  pulverized  ore;  the  other  hand 
is  used  now  for  shaking  the  pan  in 
a  gentle  but  rapid  manner.  The 
powdered  ore  being  gathered  to  one 

FIG  16  s^6j  ^e   neav7  grams   of  g°ld  de- 

scend through  the  sand  to  the  bot- 
tom of  the  pan  and  settle.  After  shaking  the  pan  a 
few  minutes,  it  is  to  be  moved  so  as  to  produce  a 
gentle  current  in  casting  off  the  water.  This  will  carry 
off  some  of  the  sand  and  diminish  the  quantity  in  the 
pan.  Fresh  water  is  now  added,  and  another  portion 
of  sand  washed  away,  this  operation  being  repeated 
until  nearly  all  the  sand  has  been  washed  from  the  pan. 
A  little  water  being  retained  in  the  pan,  the  concentrates 
are  moved  around  by  inclining  the  pan,  and  giving  the 
water  a  rocking  motion.  The  gentle  current  produced 


BATEA 


by  the  motion  will  float  the  sand  away  and  leave  the 
metal  in  view.  Assaying  by  the  pan  is  not  accurate,  as 
only  the  coarser  particles  are  retained,  the  finer  going 
off  with  the  sand.  At  times  it  is  customary  to  rock 
the  pan  back  and  forth  with  the  last  water  slightly  and 
then  make  a  line  with  the  material  remaining  by  inclin- 
ing the  pan  to  one  side.  The  gold  being  the  heavier, 
remains  at  the  point  of  the  line  in  what  is  termed  a  pen- 
cile.  If  a  batea  with  a  hole  in  the  center  has  been 
used  for  the  operation,  the  gold  may  be  separated  from 
the  sand  by  pushing  it  through  the 
hole,  after  it  has  been  collected  in  the 
center  by  a  rotary  motion. 

The  Mexican  batea  (Fig.  17)  is  a 
good  tool  for  placer  miners,  but  it 
does  not  possess  advantages  over  the 
iron  pan,  except,  perhaps,  in  the 
matter  of  collecting  sulphurets  in 
sample  assaying.  The  wooden  bowl  IG' I7' 

is  given  a  steady  circular  shake  without  revolving,  alter- 
nated with  a  reciprocating  motion,  which  settles  the 
heavier  mineral  in  the  center  of  the  bowl ;  on  inclining  it 
the  sand  flows  to  one  side.  In  washing  they  are  filled  with 
the  dirt  the  same  as  pans,  immersed  in  water,  and  stirred 
by  hand;  a  circular  motion  is  given  to  the  bowl,  which 
is  also  slightly  inclined,  allowing  the  sand  to  wash  over 
the  sides.  The  gold  sinks  to  the  bottom  and  clings  to 
the  sides  of  the  batea,  which  requires,  generally,  more 
care  in  manipulation. 

To  work  either  the  pan  or  batea  requires  care  and 
experience;  and  some  become  very  expert  in  their  use. 


66  DEVELOPMENT  OF  PLACER  MINING 

The  Rocker.  —  To  do  away  with  tedious  panning  and 
to  increase  the  quantity  of  dirt  that  could  be  washed 
in  a  given  time  some  one  invented  the  rocker. 

Rockers  are  designed  in  many  forms,  to  suit  the  ideas 
of  the  individual,  and  often  to  suit  the  material  to  be 
washed. 

The  contrivances  are  rocked  back  and  forth;  one 
swing,  however,  is  longer  than  the  other,  the  object 
being  to  settle  the  heavy  material.  In  some  cases  the 
short  swing  is  brought  to  an  abrupt  stop  by  a  block, 
but  more  often  the  man  manipulating  the  rocker  decides 
on  the  length  of  swing  from  the  fact  that  rocking  like 
panning  is  not  an  entirely  mechanical  operation,  but 
requires  skill  and  judgment.  The  dimensions,  like  the 
construction,  are  varied  to  suit  the  ideas  of  the  miner. 
A  fair-sized  rocker  is  about  6  feet  long,  24  inches  high, 
and  15  inches  wide  in  the  bottom,  and  19  inches  wide 
at  the  top  (Fig.  18).  The  floor  of  the  rocker  is  given  a 


slant,  with  the  feed  end,  B,  about  six  inches  higher 
than  the  discharge  end,  O.  This  inclination  should 
depend  upon  the  material  to  be  washed  and  the  amount 
of  water  available.  Fine  gold  should  be  given  less 
water  and  less  inclination  than  coarse  gold.  Iron  bars, 
parallel  to  the  sides  of  the  trough,  are  placed  on  edge, 
making  a  grating,  known  as  a  "grizzly."  These  bars 


AMALGAM  67 

have  end  rests,  and  if  too  limber  or  given  to  buckling 
should  be  stiffened  by  intermediate  rests.  The  spaces 
between  the  bars  are  from  f  to  J  inch.  Perforated  or 
slotted  metal  plates  are  more  convenient  and  will  answer 
the  purpose  as  well  as  bars,  besides  are  more  economical 
if  well  braced  across  the  rocker.  A  current  of  water  is 
let  in  at  the  upper  end  of  the  rocker,  on  the  ore;  this 
water  passes  through  the  grating,  carrying  the  finer 
material,  sand  and  gold,  with  it  into  the  box,  C.  If 
the  gold  is  fine,  quicksilver  is  placed  in  small  quantities 
in  the  box,  to  form  an  alloy  termed  amalgam.  The 
light  sand  in  C  is  swept  out  by  the  current  of  water 
which  passes  through  the  grating  at  O.  At  each  swing 
the  coarser  dirt  which  does  not  go  through  the  bars  is 
moved  by  the  jar  towards  the  discharge,  O.  The  jar 
may  not  be  sufficient  to  dispose  of  the  coarse  material, 
in  which  case  the  miner  uses  his  shovel  for  that  purpose. 
While  rocking  is  quite  effective  for  coarse  gold,  there  is 
much  fine  float  gold  lost  even  when  quicksilver  is  em- 
ployed. This  is  especially  the  case  when  much  clay  is 
present  as  that  encases  both  coarse  gold  and  fine,  and 
since  the  specific  gravity  of  the  two  combined  is  less 
than  for  gold  alone,  the  density  of  muddy  water  may  be 
sufficient  to  buoy  the  fine  particles,  which  float  away 
in  the  agitated  current  of  water.  Mercury  cannot  reach 
fine  gold  smeared  with  clay,  and  it  may  be  worth  while, 
therefore,  to  go  slower  and  use  more  water  to  wash  off 
the  clay. 

Where  there  is  much  clay  a  good  plan  is  to  feed  the 
material  and  water  into  a  trough,  and  allow  the  dirt  to 
be  moved  by  the  water  along  the  trough  and  discharged 


68 


DEVELOPMENT  OF  PLACER  MINING 


into  the  rocker.  The  clay  will  be  washed  more  thor- 
oughly from  the  gold  by  this  means,  and  the  latter  be 
given  a  better  opportunity  to  form  amalgam. 

Another  form  of  rocker  is  shown  in  Fig.  19.  This 
is  a  box  with  sloping  sides,  about  36  to  42  inches  long 
and  1 6  inches  wide,  with  a  rocker  near  the  middle  and  one 
near  the  back.  There  is  a  hopper,  H3  20  inches  square, 


FIG.  19. 

4  inches  deep,  whose  iron  bottom  is  perforated  with 
|-inch-diameter  holes.  This  hopper  is  removable. 
Under  this  hopper,  on  a  light  inclined  frame,  C,  a  canvas 
apron,  A,  is  stretched,  to  form  a  riffle.  The  water  is 
poured 'on  the  dirt,  which  is  shoveled  into  the  hopper, 
washes  the  .gold  and  sand  through  the  screen,  after 
which  the  coarse  material  in  the  hopper  is  thrown  aside 
and  new  dirt  substituted.  The  rocker  has  pieces  of 
plank,  Rj  nailed  transversely  across  the  bottom,  to 
catch  the  gold  as  the  current  transports  the  sand  to  the 
discharge  end. 

The  rocker  shown  in  Fig.  20  is  used  in  the  South, 
and  those  natives  who  have  the  gold  fever  consider 
it  the  best  apparatus  for  washing  dirt  in  existence.  Al- 
though it  is  a  crude  affair  it  is  nevertheless  effective  in 


CRADLES  69 

the  hands  of  one  accustomed  to  its  manipulation.  The 
Southern  placer  gold  is  fine,  most  of  it  being  mere  colors, 
so  that  pieces  from  the  size  of  mustard  seed  up  are 
called  nuggets. 

Men  cannot  pan  sufficient  quantities  of  this  dirt  to 
make  wages,  but  with  a  rocker  can  treat  from  2  to  2j 
cubic  yards  daily. 
The  rocker  has  two 
longitudinal  riffles, 
a,  placed  about  as 
in  the  cross-section. 
The  riffles  are  about 
the  thickness  and 

width  of  bed  slats,    FIG.  20.     North  Carolina  Trough  Washer, 
the  object  being  to 

retain  the  black  sands  and  gold  between  the  two. 
The  dirt  to  be  washed  is  shoveled  into  the  tub  until 
the  bottom  is  covered.  Water  is  next  poured  in  and 
the  apparatus  rocked  to  clean  the  mud  from  the 
larger  pieces  of  stone.  The  cradle  is  then  tilted 
until  the  dirty  water  will  run  out  of  plug  holes,  b,  after 
which  the  larger  pieces  of  rock  are  raked  out  over 
the  side.  This  operation  is  repeated  until  the  water 
poured  in  and  agitated  remains  comparatively  clear, 
and  there  are  but  few  small  stones  in  the  tub.  Expert 
work  now  begins,  the  object  being  to  wash  the  light 
sands  over  one  riffle  and  leave  the  gold  and  heavy  black 
sands  between  the  two  riffles.  To  accomplish  this 
a  quick  jerk  is  given  the  rocker  one  way,  and  then  as  the 
water  moves  to  one  side  it  is  allowed  to  come  to  rest 
slowly  and  flow  back.  The  motion  is  similar  to  that 


70  DEVELOPMENT  OF  PLACER  MINING 

given  a  pan  when  a  pencil  of  black  sand  is  being  formed, 
except  that  the  height  of  the  wave  movement  is  decreased 
gradually  on  one  side  of  the  tub  and  increased  on  the 
other  until  all  the  light  sands  are  on  the  long-wave  side. 
When  this  is  accomplished  the  heavy  sands  are  between 
the  riffles,  and  the  gold  is  picked  out.  Expert  manipu- 
lators of  these  cradles  claim  that  they  can  save  90  per 
cent  of  the  gold.  They  do  not  use  mercury  either  in 
the  cradle,  or  in  the  clean-up,  from  the  fact  that  it  costs 
money,  becomes  foul  quickly,  needs  retorting,  and 
must  be  cleaned  before  it  will  amalgamate  properly,  all 
of  which  means  extra  labor  and  expense,  which  they 
cannot  stand,  with  such  small  operations. 

Combination  rockers,  such  as  were  used  at  Gold  Hill, 
North  Carolina,  are  made  by  connecting  several  single 
rockers  by  rods,  the  pulp  being  conveyed  to  them  by  a 
trough.  The  riffles  in  these  rockers  are  crosswise  of 
the  trough  and  only  one  end  is  closed,  making  it  virtually 
a  rocking  sluice  box.  A  woman  often  furnished  the 
motive  power,  shifting  her  weight  alternately  from  one 
side  of  one  rocker  to  the  other.  In  many  instances  these 
rockers  were  used  as  concentrators  in  conjunction  with 
Chilean  mills. 

The  Long  Tom  is  a  short  sluice  box  that  is  used  in 
place  of  the  rocker  in  suitable  localities.  It  requires 
one  man  to  feed  it  and  another  to  keep  it  in  working 
order.  It  is  capable  of  washing  6  yards  of  ordinary 
dirt,  and  from  3  to  4  yards  of  cemented  dirt  in  10  hours. 
The  material  to  be  washed  is  shoveled  into  the  sluice 
box,  H,  Fig.  21,  and  that  being  supplied  with  an  abund- 
ance of  flowing  water,  carries  the  dirt  to  the  torn.  The 


LONG  TOM  71 

feed  end  of  the  torn  is  about  18  inches  wide,  while  the  dis- 
charge end  is  about  32  inches  wide,  and  terminates  in 
a  perforated  sheet-iron  plate,  P.  As  the  material  enters 
at  £T,  it  spreads  out  until  it  meets  the  plate,  P,  where  it 
is  immediately  riddled  and  so  assorted,  that  all  stuff 
finer  than  one-half  inch  in  diameter  falls  with  the  water 
into  a  second  trough,  T,  one  end  of  which  is  underneath 


FIG.  21. 

the  plate.  The  coarse  material  is  shoveled  off  the  plate, 
and  the  lumps  of  clay  and  dirt  thrown  up  towards  the 
head  so  that  the  water  will  have  another  chance  to 
disintegrate  them. 

In  order  to  facilitate  the  movement  of  material  in 
the  troughs  the  latter  are  placed  on  timbers  or  stones  to 
give  them  a  slope  towards  the  discharge.  The  lower 
box  is  furnished  with  transverse  riffles,  R,  which  collect 
the  gold  that  moves  with  the  stream  of  water.  The 
constant  movement  of  the  water  beneath  the  plate 
keeps  the  sand  suspended  and  allows  the  gold  to  sepa- 
rate and  sink  by  gravity  to  the  floor  of  the  trough.  The 
inclination  of  the  riffle  box  should  be  such  that  the 
bottom  of  the  trough  is  covered  with  a  thin  coating  of 
mud,  and  is  not  scoured  by  swiftly  running  water  and 
sand. 

Mercury  can  be  used  in  the  riffles  to  assist  in  retaining 
the  gold,  and  the  riffle  box  can  be  supplemented  with 


72  DEVELOPMENT  OF  PLACER  MINING 

another  box  containing  blankets  or  hides  with  the  hair 
turned  up  stream  to  catch  the  fine  gold.  In  the  latter 
case  a  fine  screen  with  not  larger  than  n  inch  mesh 
holes  should  be  placed  above  the  blanket,  in  order  to 
prevent  coarse  sand  and  gravel  from  traveling  over  and 
wearing  it.  On  Snake  River,  Idaho,  very  fine  float 
gold  has  been  saved  by  such  means. 

Sluicing  is  a  term  used  to  indicate  the  process  of 
washing  dirt  through  a  channel  by  means  of  water. 
The  channel  through  which  the  dirt  is  transported  may 
be  a  wooden  trough,  or  a  ditch  cut  in  bed  rock.  The 
sluice  is  the  most  important  part  of  any  hydraulic  min- 
ing system,  and  if  it  is  not  constructed  properly  there 
will  be  a  loss  of  gold.  The  earth  may  be  fed  to  the 
sluice  by  hand,  or  indirectly  by  machinery,  or  it  may  be 
washed  from  a  bank  by  a  stream  of  water  that  is  after- 
wards led  to  the  sluice. 

Fig.  22  shows  a  hand  sluice  into  which  the  miners 
shovel  the  gold-bearing  dirt,  previously  picking  out  the 
large  stones  and  throwing  them  one  side.  Similar  sluice 
boxes,  although  much  larger  and  stronger,  are  used 
where  mechanical  apparatus  is  employed  for  excavating. 

The  water  in  flowing  through  the  sluice  transports  the 
material  to  the  dumping  ground,  and  at  the  same  time 
washes  the  gold  free  from  rocks  to  which  it  is  adhering, 
and  permits  it  to  fall  to  the  bottom  of  the  sluice,  where 
it  is  caught  in  artifical  traps  called  riffles.  There  should 
be  arrangements  to  prevent  large  stones  entering  a  small 
sluice  as  they  wear  the  boxes,  require  more  water  for 
their  transportation,  or  else  a  heavier  grade,  than  do 
smaller  stones,  and  are  otherwise  objectionable.  In 


74 


GROUND  SLUICES  75 

many  cases  all  material  to  be  washed  passes  through 
grizzlies  that  prevent  stones  larger  than  3  inches  in 
diameter  from  entering  the  sluice. 

In  ground  sluicing  this  is  not  always  practicable,  as 
the  material  is  delivered  so  fast  screens  would  become 
clogged,  for  which  reason  a  man  stands  at  the  head  of 
a  sluice  and  pulls  out  the  largest  stones,  and  prevents 
the  others  from  clogging  the  entrance.  Ground  sluices 
are  bed-rock  sluices,  and  must  be  constructed  with  great 
care,  as  much  depends  upon  them.  They  are  objec- 
tionable because  they  can  be  cleaned  up  only  once  in  a 
season,  and  because  all  boulders  have  to  be  removed  out 
of  the  way  by  derricks.  The  motive  power  for  the  der- 
ricks is  obtained  usually  from  water,  and  a  Pelton  water 
wheel. 

Upon  the  construction  and  operation  of  a  sluice  much 
of  the  success  of  placer  mining  depends.  Steadiness  of 
flow,  that  is,  the  quantity  of  water  passing  and  its  velocity 
should  be  uniform  to  secure  a  maximum  settling  of  the 
gold.  To  be  sure  it  is  not  always  possible  to  prevent 
crowding  a  sluice,  particularly  when  caving  a  bank,  but 
there  is  no  economy  in  doing  so,  and  generally  an  experi- 
enced pipeman  can  avoid  it.  If  the  bank  runs  in  too 
freely  so  as  to  send  large  quantities  of  dirt  to  the  sluice, 
it  may  be  economical  to  construct  other  sluices.  The 
bulk  of  the  gravel  and  boulders  travel  down  the  middle 
of  a  sluice,  hence  its  grade  and  depth  are  important, 
yet  the  fact  that  a  swift  current  while  able  to  transport 
heavy  material  will  not  permit  fine  gold  to  settle  must 
not  be  overlooked. 

The  sectional  area  of  a  sluice  will  depend  upon  the 


76  DEVELOPMENT   OF  PLACER  MINING 

quantities  of  water  and  dirt  it  is  to  carry.  An  ordinary 
sluice  will  probably  be  made  of  2-inch  planks,  12  inches 
wide  and  12  feet  long.  This  sized  lumber  will  furnish 
a  box  12  inches  wide  by  10  inches  high.  The  boxes  are 
generally  made  in  1 2-foot  lengths,  and  as  many  placed 
end  to  end  as  the  nature  of  the  ground  demands.  They 
should  be  caulked  with  cotton  wick  if  oakum  is  not 
readily  attainable,  to  prevent  leakage,  and  if  they  are 
to  carry  fair-sized  stones  should  have  false  bottoms, 
which  may  be  made  to  act  as  riffle  bars. 

The  sluice  boxes  should  be  placed  in  a  straight  line, 
but  if  curving  is  necessary,  the  outer  edge  of  the  curve 
should  have  an  elevation,  to  prevent  the  material  from 
piling  up  and  clogging  the  box  when  the  direction  of 
the  flow  is  changed.  There  should  be  at  least  one  inch 
elevation  for  each  degree  of  curvature,  but  even  this 
will  not  in  all  instances  prevent  retardation  after  the 
curves  have  been  passed,  making  it  necessary  to  give  a 
slightly  greater  fall  below  the  curve  in  order  to  obtain 
uniform  flow  of  material  and  clear  the  curves. 

The  grade  necessary  to  give  a  sluice  will  depend  upon 
the  character  of  the  alluvions;  large,  heavy  stuff  will 
require  a  steeper  incline  than  lighter  material.  The 
amount  of  water  at  command  will  influence,  in  a  meas- 
ure, the  gradient,  and  the  sectional  area  of  the  sluice 
must  also  depend  upon  it.  Heavy  material  must  be 
covered  by  water,  and  a  steep  enough  grade  given  to 
have  gravity  give  velocity  to  the  water  and  exert  some 
little  action  upon  the  material;  naturally,  then,  were  the 
sluice  broad,  300  cubic  feet  of  water  per  minute  might 
be  required,  where  with  but  half  that  supply  of  water 


SIZE   OF  SLUICE  BOX  77 

the  sluice  must  be  narrowed  or  otherwise  a  very  steep 
gradient  given  it.  Narrowing  the  sluice  would  be  the 
most  satisfactory  arrangement. 

The  length  of  the  sluice  depends  upon  dumping- 
ground  and  its  distance  from  the  workings;  yet,  were 
the  dump  close  at  hand  the  sluice  must  have  sufficient 
length  to  thoroughly  wash  the  alluvions,  and  break  up 
the  cemented  gravel,  and  the  clay. 

The  size  of  a  sluice  is  to  be  determined  by  the  amount 
of  gradient  at  command,  the  character  of  the  material, 
and  the  quantity  of  water  which  may  be  used. 

The  grade  of  a  sluice  will  depend  upon  the  fall  of 
the  ground  to  the  dump,  the  character  of  the  material 
transported,  and  the  amount  of  water  at  command. 
The  grade  will  vary  from  2  to  15  per  cent,1  or  from  2  to 
15  feet  in  every  100  feet  of  length,  or  from  2.8  inches  to 
21.6  inches  per  box  12  feet  long.  The  grade  should  be 
determined  previously  by  experiment  before  permanently 
placing  the  sluice  in  position,  otherwise  there  may  be 
considerable  loss  of  both  gold  and  amalgam,  to  remedy 
which  may  require  the  raising  of  the  whole  sluice  line, 
or,  if  the  fall  is  not  sufficient,  its  lowering.  It  is  impor- 
tant that  the  sluice  has  sufficient  fall,  and  a  proper 
dumping  ground,  also  it  should  be  near  the  level  of  the 
ground  where  the  dirt  is  to  enter  it. 

As  low  as  ij  per  cent  grade  has  been  used. 

The  sluice  has  advantages  over  any  other  system  both 
for  collecting  free  gold  and  the  removal  of  barren  dirt 
in  an  economical  manner,  consequently  the  attention 

1  Bowie,  Alex.  J.,  p.  219. 


78  DEVELOPMENT  OF  PLACER  MINING 

given  to  its  construction  and  the  work  it  performs  will 
prove  remunerative. 

Where  gravel  is  to  be  sluiced  for  some  distance,  the 
boxes  should  be  stepped,  in  order  to  effect  a  drop  that 
will  shake  up  the  material.  Sand  is  apt  to  sink  and 
move  along  the  sluice  in  a  sluggish  and  compact  manner, 
and  in  order  to  shake  it  up  and  permit  the  heavier  par- 
ticles, i.e.,  gold  and  black  sands,  to  move  along  the 
bottom  of  the  sluice  to  a  riffle,  a  step  here  and  there  is 
necessary. 

The  construction  of  a  sluice  box  depends  for  details 
upon  the  size  required;  one  6X3  feet  would  require 
heavier  sills  and  flooring  than  one  3  X  1.5  feet. 

The  sills  should  be  three  feet  apart  and  be  twice  as 
long  as  the  width  of  the  sluice,  provided  there  is  noth- 
ing to  prevent  this  construction. 

The  posts  are  regulated  in  height  to  accommodate  the 
water  and  material;  in  this  connection  it  may  be  stated 
that  wide  sluice  boxes  lessen  the  water  pressure  on  the 
material  transported,  and  are,  therefore,  more  satis- 
factory. However,  the  kind  of  material  must  determine, 
in  a  measure,  this  point.  The  bottom  planks  should 
be  made  of  clear  lumber  and  grooved  to  admit  of  a  dry 
pine  or  other  tongue  being  inserted  into  the  groove. 
These  planks  are  placed  lengthwise  of  the  sluice  and 
securely  fastened  to  the  sills.  They  should  be  pur- 
chased in  widths  to  conform  to  the  total  width  of  the 
sluice,  to  avoid  expense  in  transportation  and  unneces- 
sary delay  in  placing  them.  If  a  tight  floor  is  to  be  had, 
half-seasoned  plank,  not  less  than  ij  inches  thick 
should  be  used.  The  side  planks  should  be  worked  in 


SLUICE   BOX  CONSTRUCTION 


79 


a  similar  manner  to  the  bottom  planks,  and  should 
extend  to  the  sills,  however  in  some  cases  one  inch 
boards  with  battens  are  used,  and  in  others  planks  not 
tongued  and  grooved  but  battened  and  caulked.  The 
side  linings  should  be  rather  thicker  than  the  side  planks, 
and  may  be  rough  plank.  Where  riffles  are  inserted 
they  do  not  reach  to  the  bottom  plank;  in  all  other 


FIG.  23. 

instances  they  should,  to  avoid  wear  on  the  side  planks. 
The  posts  are  braced  every  alternate  sill  by  means  of 
i  J-inch  plank  strip,  as  shown  in  Fig.  23. 

To  avoid  wear  upon  the  bottom  plank,  rough  plank 
must  be  nailed  over  them.  This  should  be  hard  wood, 
if  possible;  beech  or  maple  will  be  found  to  wear  smooth 
and  uniform,  where  oak  splinters. 

The  cost  of  the  sluice  box  will  depend  upon  the  locality, 
the  price  of  lumber,  nails,  and  labor  per  diem  in  that 
locality,  as  well  as  transportation. 

The  great  advantage  possessed  by  sluicing  in  saving 
gold  is  due  to  the  thorough  washing  the  material  obtains, 
but  the  necessity  for  the  erection  of  retaining  dams  to 
catch  the  tailings  has  in  recent  years  greatly  retarded 
the  system  in  California  and  consequently  the  output  of 
that  state. 


8o  DEVELOPMENT  OF  PLACER  MINING 

Sluices  should  be  at  least  240  feet  long  and  set  in  as 
straight  a  line  as  possible,  otherwise  fine  gold  and  mer- 
cury may  pass  through.  A  sluice  500  feet  long  had 
frames  5X7  inches,  with  a  box  60  inches  wide  by  30 
inches  deep  inside,  it  was  lined  on  the  bottom  with  2- 
inch  planks  and  on  the  sides  with  i-inch  boards.  The 
floor  lining  was  6x6  inches  blocks  10  inches  long  of 
sawed  lumber.  Another  sluice  2000  feet  long  was  paved 
with  blocks. 

Figure  24  shows  two  sluice-box  lines  at  Bullion, 
British  Columbia,  where  hydraulicking  is  practiced. 

Transporting  Power  of  Water. — Water  will  carry  dirt 
in  suspension,  and  thereby  increase  its  density;  it  must 
however  have  a  current,  otherwise  it  will  precipitate  the 
dirt.  If  the  current  is  swift  and  the  water  deep  only  the 
heavy  particles  will  be  precipitated,  but  if  the  water  is 
suddenly  spread  out  and  the  current  reduced  the  light 
particles  will  fall  to  the  bottom.  It  is  upon  this  principle 
that  the  sluice  and  undercurrent  are  constructed;  the 
first  being  intended  to  transport  all  dirt  and  water  that 
is  not  too  heavy,  and  the  second  being  for  the  purpose  of 
recovering  light  particles  of  gold  that  are  not  sufficiently 
heavy  to  sink  in  a  swift  running  stream.  The  dirt  when 
in  suspension  adds  to  the  density  of  the  liquid  and  hence 
to  its  transporting  power.  This  may  be  better  understood 
by  considering  the  momentum  exerted  by  water  moving 
at  a  given  velocity  in  feet  per  second.  One  cubic  foot  of 
water  will  weigh  62.5  pounds,  and  if  it  move  at  the  rate 
of  10  feet  per  second,  will  have  a  momentum  of  625 
pounds.  The  weight  of  a  cubic  foot  of  wet  sand  is  twice 
that  of  water,  125.0  pounds.  Supposing  i  cubic  foot  of 


82 


FIG.  24. 


TRANSPORTING  POWER  OF   WATER  83 

material  and  water  passing  along  the  sluice  to  be  com- 
posed of  two-thirds  water  and  one-third  sand,  the  weight 
would  be  82.6  pounds,  and  the  momentum  at  the  above 
velocity  826  pounds,  thus  increasing  the  transporting 
capacity  of  the  water  one-third.  The  density  of  the 
water  having  been  increased  one-third,  its  ability  to  float 
material  has  been  increased  one- third;  or,  expressed  in 
momentum  (as  far  as  the  rock  in  the  sluice  is  concerned, 
whose  specific  gravity  relative  to  the  fluid  is  decreased 
one-third  as  compared  with  water),  noi  pounds.  The 
transporting  capacity  of  such  a  combination  is  therefore 
nearly  double  that  of  water  alone,  hence  the  coarse  and 
heavy  material  moves  along,  not  on  the  bottom  of  the 
sluice,  but  above  the  bottom  and  below  the  water.  This 
combination  will  move  rocks  that  aid  by  their  movement 
to  disintegrate  and  wash  out  the  gold  from  the  dirt  that 
may  hold  it  encased  or  in  suspension,  and  also  prevent 
sand  from  packing.  Heavy  rocks  will  not  have  the  same 
velocity  as  lighter,  but  their  colliding  has  a  grinding 
effect  upon  the  material  containing  the  gold.  There  are 
no  experiments  of  such  a  nature  as  to  formulate  a  rule 
by  which  the  gradients  being  known  the  transporting 
capacity  can  be  determined.  According  to  Le  Conte, 
"If  the  surface  of  running  water  be  constant,  the  force 
of  running  water  varies  as  the  square  of  its  velocity,  and 
the  transporting  power  of  a  current  as  the  sixth  power 
of  the  velocity."  l  Friction  increases  as  the  square  of  the 
velocity 'and  as  the  cube  of  the  density;  however  the 
same  liquid  will  vary  in  density  in  the  same  sluice,  to  a 
wide  degree.  Le  Conte  says:  "The  transporting  power 

1  Elements  of  Geology,  pp.  19,  20. 


84  DEVELOPMENT  OF  PLACER  MINING 

of  water  will  be  between  the  square  and  sixth  power  of 
its  velocity."  According  to  Smeaton,  a  velocity  of  8 
miles  an  hour  will  not  derange  quarry  rubble  stones, 
deposited  around  piers,  provided  they  do  not  exceed  half 
a  cubic  foot,  except  by  washing  the  soil  from  under  them. 
The  transporting  capacity  of  water  in  sluice  boxes  will 
be  greater  than  in  rivers  from  the  fact  that  they  are 
smooth  and  straight  and  of  uniform  width. 

The  Size  of  Sluice  Boxes.  —  Sluice  boxes  should  be 
calculated  for  carrying  capacity,  but  in  order  to  do  this 
they  must  be  calculated  from  the  quantity  of  water  that 
is  to  flow  through  them.  The  maximum  quantity  of 
water  that  can  be  used  to  advantage  in  a  single  sluice 
is  stated  to  be  1000  miners'  inches  or  90,000  cubic 
feet  per  hour,  a  miners'  inch  being  legally  in  Cali- 
fornia 1.5  cubic  feet  per  minute.  If  there  is  more 
than  this  quantity  of  water  at  command,  two  sluices 
should  be  used,  for  a  greater  flow  takes  the  workmen 
off  their  feet. 

It  is  a  difficult  matter  to  calculate  the  size  of  sluice 
boxes  owing  to  the  uncertainty  of  the  size  of  the  material 
they  are  to  carry,  consequently  assumptions  must  be 
made  and  calculations  made  to  agree  with  them 

The  area  of  a  sluice  is  to  be  calculated  in  square  feet, 
thus  a  sluice  2X3  feet  is  6  square  feet  in  area,  and  if 
such  a  sluice  were  10  feet  long  it  would  contain,  when 
full  of  water,  60  cubic  feet.  If  this  box  were  given  a 
slant  of  i  foot,  it  would  have  a  grade  of  i  foot  in  10 
feet  or  10  per  cent,  and  the  water  would  flow  with  a 
velocity  found  by  the  formula 

v  =  \/2  gh, 


RUBBING   SURFACE  85 

in  which  v  =  velocity,  2  g  =  64.32  the  acceleration  of 
gravity  at  the  end  of  the  first  second;  and  h  the  height 
of  fall  or  grade  which  in  this  case  is  i  foot.  Substitu- 
ting these  values 

v  =  ^64.32  X  i  =  8.02, 

or  the  velocity  in  feet  per  second  which  the  water  would 
have  at  such  a  grade. 

The  flow  would  be,  if  there  were  no  other  interfering 
factors,  8.02  X  6  =  48.12  cubic  feet  per  second.  But 
there  are  other  interfering  factors  such  as  frictional 
resistance,  which  increases  as  the  rubbing  surface  in- 
creases and  as  the  velocity  of  the  water  increases. 

The  rubbing  surface  is  the  surface  wet  by  the  flowing 
water,  and  in  the  example  cited  it  is  2  +3  +2  =  7  feet. 
This  wetted  surface  or  rubbing  surface  is  termed  the 
wet  perimeter  and  must  enter  into  the  calculations 
as  it  retards  the  flow  of  water.  If  the  channel  has 
smooth  sides  such  as  wooden  sluice  boxes  usually  do 
have,  the  friction  is  less  than  in  ditches,  consequently  the 
size  and  grade  may  be  less  for  the  same  volume  of  water. 

Before  entering  into  the  calculation  of  the  carrying 
capacity  of  sluice  boxes  there  are  some  terms  that 
should  be  explained. 

The  area  of  a  sluice  box  is  the  number  of  square 
feet  or  square  inches  in  its  vertical  cross- 
section.     The  area  is  found  by  multi- 
plying   the    width    by  the    depth;   for 
example,  Fig.  25,  1.5'  X  3'  =  4-5  square 


FIG.  25. 
feet  is  the  area  of  the  box;  or  18"  X 

36"  =648  square  inches  is  the  area  of  the  box  in  square 
inches.      In  calculations  of   this    kind  inches  must  be 


86  DEVELOPMENT  OF  PLACER  MINING 

multiplied  by  inches  and  feet  by  feet,  but  either  may 
be  reduced  readily  to  the  other;  thus 

4.5'  X  144"  =  648  square  inches; 

648* 

and  —  —f  =4.5  square  feet. 


Another  term  of  frequent  occurrence  in  hydraulics 
is  wetted  perimeter.  The  perimeter  of  a  figure  is  its 
boundary  lines,  and  is  measured  by  the  length  of  those 
lines,  thus  in  Fig.  25  the  perimeter  is 

1.5'  +  3'  +  1.5'  =  6  feet. 

The  wet  perimeter  of  a  sluice  box  is  the  border  of  the 
box  in  actual  contact  with  the  water,  thus  in  Fig.  25  if 
the  water  was  running  12  inches  deep  in  the  box,  only 
i  foot  on  each  side  of  the  box  would  be  wet,  consequently 
the  wet  perimeter  would  be  1+3+1  =  5  feet  or 
60  inches.  The  water  area  in  this  case  would  be 
3X1=3  square  feet. 

The  mean  hydraulic  radius  is  equal  to  the  water 
area  of  the  sluice,  divided  by  the  wet  perimeter,  for 
example,  the  water  area  in  the  illustration  is  assumed 
as  3  square  feet  and  the  wet  perimeter  as  5  feet,  hence 
the  mean  hydraulic  radius  is  |  =  .6  feet. 

The  mean  hydraulic  radius  is  called  at  times  the 
hydraulic  mean  depth,  and  hydraulic  radius. 

If  a  sluice  box  12  feet  long  had  a  water  area  of  3 
square  feet  it  could  contain  when  horizontal  3  X  12  = 
36  cubic  feet  of  water.  If  the  box  were  tipped  so  that 
one  end  was  6  inches  higher  than  the  other,  the  water 
would  flow  to  the  lower,  end  with  a  velocity  equivalent 
to  so  many  feet  per  second.  If  there  was  nothing  to 


VELOCITY  OF  FLOW  87 

prevent  the  flow  of  this  water  it  would  have  a  velocity 
according  to  the  formula 

v  =  \/2  ghj 

in  which  v  stands  for  velocity  g  for  the  acceleration  of 
gravity  =  32.16;  and  h  for  head  or  height  of  fall.  Sub- 
stituting the  values  of  the  example  in  this  formula, 

v  =  \/2  X  32.16  x  .5  =  \/32.i6  =  5.76  feet  per  second 
as  the  velocity.  To  find  the  quantity  of  water  that 
would  flow  with  such  a  head,  under  such  theoretical 
conditions,  all  that  is  necessary  is  to  multiply  the  area 
by  the  velocity  or  3  X  5.76  =  17.78  cubic  feet  per 
second.  There  are  several  matters  which  enter  into 
such  calculations,  that  prevent  the  theoretical  quantity 
of  water  from  being  realized  in  practice.  There  must 
be  an  allowance  made  for  retardation  due  to  friction; 
moreover  the  wetted  or  water  area  only  has  been  con- 
sidered, and  when  transporting  material  the  wet  peri- 
meter will  be  increased  from  20  to  35  per  cent  of  the 
depth  of  the  water  alone. 

In  rectangular  sluice  boxes,  the  wet  perimeter  is 
smallest  and,  therefore,  the  friction  least,  when  the 
width  of  the  box  is  from  if  to  2\  times  the  vertical 
depth.  In  all  cases  the  boxes  should  not  run  more 
than  |  full. 

When  the  area  needed  to  convey  the  quantity  of 
water  at  the  given  velocity  is  ascertained,  it  is  neces- 
sary to  find  what  form  the  area  shall  take. 

The  formula  for  finding  the  area  is 


88  DEVELOPMENT  OF  PLACER  MINING 

in  which     a  =  area  in  square  feet  or  square  inches, 

q  =  quantity  of  water  flowing  in  cubic  feet 

per  second. 

In  the  former  example,  the  area  was  assumed  and  the 
velocity  and  quantity  calculated  to  the  conditions.  This 
was  not  the  best  form  of  a  sluice  as  the  wet  perimeter 
and  consequently  friction  was  increased:  assume,  how- 
ever, that  the  area  was  the  same  (3  square  feet),  but 
the  bottom  width  was  if  times  the  height,  then  to  find 
the  proper  cross-sectional  area  for  this  width; 

"  Multiply  the  given  area  in  square  feet  or  square  inches 
by  4,  and  divide  by  7  ;  the  square  root  of  the  quotient  will 
be  the  depth  in  feet  or  inches" 

Example.  —  What  will  be  the  depth  in  feet  of  a  sluice 
box  having  an  area  of  3  square  feet,  when  the  width  of 
the  bottom  is  if  times  its  height? 


- 


Solution.  —    —  -  —  =      i.  714  =  1.309.     Ans. 

If  the  width  is  to  be  2j  times  the  depth  or  side, 
"  multiply  the  given  area  in  feet  or  inches  by  4,  and  divide 
by  9;  the  square  root  of  this  quotient  will  be  the  depth  in 
feet  or  inches." 

Take  the  area  3  square  feet  as  before. 

3  X  4    =  Vi.333  =  1.15.     Ans. 

This  gives  a  larger  area  than  where,  the  rubbing  surface 
is  not  considered.  Probably  the  tfest  width  relative  to 
the  depth  is  2  to  i. 

Grade.  —  To   create  a  uniform  flow  the   sluice   must 
be  given  a  grade  that  will  produce  the  required  velocity. 


CALCULATING   SLUICE   GRADIENTS  89 

This  must  necessarily  vary  according  to  the  material 
to  be  transported,  since  coarse  material  will  require  a 
steep  grade  or  a  large  quantity  of  water,  while  fine 
material  will  not  require  a  very  steep  grade  or  much 
water. 

The  grade  given  a  sluice  box  varies  from  2  to  16 
inches,  a  box  being  12  feet  in  length.  The  average 
grade  is  probably  6  inches  for  a  1 2-foot  box,  where  the 
gravel  comes  from  a  bank  that  is  hydraulicked.  The 
grade  once  determined  should  be  adhered  to  and  only 
broken  at  undercurrents. 

To  calculate  a  sluice  gradient  to  produce  a  given  flow 
of  water  use  the  following  deduced  formula 

v  =  c  \/2  grs. 
In  this  formula 

total  fall  in  feet  or  inches 


=  sine  of  inclination  or 


total  length  in  feet  or  inches 
c  =  a  coefficient  determined  experimentally  for  rough 

planks  to  be  .8. 
g  =  32.16,  and  is  the  acceleration  in  i  second  due  to 

gravity. 
v  —  velocity  in  feet  per  second. 

,     ,       ,.  ,.          sectional  area      a 

r  =  hydraulic  mean  radius  or  -  ;  -  =  —  • 

wet  perimeter      p 

Example.  —  The  water  area  of  a  sluice  box  is  2 
square  feet;  the  perimeter  of  the  box  is  4  feet;  the  grade 
is  6  inches  in  12  feet;  What  will  be  the  velocity  of 
flow?  What  will  be  the  quantity  of  water  passing? 

2  ^ 

Solution.  —  r  =  —  =.<.    s  =  -^  =  .0416 

4  12 


go  DEVELOPMENT  OF  PLACER  MINING 

then  by  substituting  in  formula 


.8^/32.16  X  2  X  .5  X  .0416 


=  .8Vi.  337856  =.8  X  1.156  =  .92  feet  per  second. 

q  =  va  =  .92  X  2  =  1.84  cubic  feet  per  second.    Ans. 

In  the  above  example  the  grade  s  was  given,  however, 
to  find  a  grade  that  will  furnish  a  given  velocity,  the 
above  formula  is  factored  until  it  assumes  the  form 


c2  2  gr 

Example.  —  What  grade  must  be  given  a  box  whose 
water  area  is  2  square  feet,  and  whose  perimeter  is  4 
feet,  in  order  to  produce  a  flow  of  1.84  cubic  feet  per 
second. 

Solution.  — v  a*  *•  as  -i-3  ==  .02  feet  per  second. 
a         2 

c22  gr  ~  .82  X  2  X  32.16  X  .5   ~  20.58  ~ 
sine  of  inclination,  and  hence 

.0416  X  12'  =  .499  or  .5  feet  in  12  feet.     Ans. 
In  order  to   find  the  dimensions  of  a  sluice  box  that 
will  carry  a  given  quantity  of  water,  the  empirical  formula 

,000  r2s 


6.6  r  +  .46 
is  adopted  by  many  engineers. 

In  this  formula  r  is  the  hydraulic  radius,  and  s  is 

the  slope  of  the  sluice,  or  —  • 

Example  (i).  — It  is  required  to  compute  the  dimen- 
sions of  a  sluice  to  convey  2.82  cubic  feet  of  water  per 


SLUICE  BOX  CALCULATIONS  91 

second  with  a  grade  of  6  inches  in  12  feet,  the  width  of 
the  sluice  to  be  twice  the  depth  of  the  water  flowing 
through  ito 

Solution.  —  Let  x  =  depth  of  water  in  the  flume ; 
then  the  width  will  be  2  x  and  the  wet  perimeter  =  4  x. 

The  water  area  will  be  2  x2,  and  the  hydraulic  radius 

O    'Y*  *V  'V* 

r  =  =  —  >   consequently  r2  =  —  .      The   slope   is 

4*2  4 

= — .     As  the  discharge  is   to   be  2.82    cubic 

12  X  12      24 


ry     X  O 

feet  per  second,  the  mean  velocity  will  be  -J— - 

2X2  X 

Substituting  these  values  in  the  formula 

1?       T* 

100,000  X  —  X  — 
1.41  /     4        24    ^ 

6.6  X  -  +  .46 

2 

Squaring 

•V*  T 

100,000  X  —  X  — 
4        24  _      ioo,oooar 

6.6  X  -  +  .46 

2 

then 

6.56073  x  +    .914526  = 

3 
Multiplying  by  3 

19.68219  x  +  2.743578  =  3125  x9. 
Dividing  by  3125 

x6  —  .006  x  =  .0008779. 
If  x  =  .383 


92  DEVELOPMENT  OF  PLACER  MINING 

then  .063156  —  .002298  =  .0008584, 

which  is  close  enough  to  the  second  term  of  the  equation 

and  hence 

#  =  -383  X  12  =  4.596  inches. 
2  x  or  width  of  sluice  =  2  X  4.596  =  9.192  inches. 
4  x  or  wet  perimeter  =  4  X  4.596  =  18.384  inches  or 

ij  feet. 
To  prove  this 

4.596  +  4.596  +  9.192  _      feet 

12 

for  wet  perimeter.     Area  of  water  section 

9.192X4.596  e 

*—~* >7y   =  .293  square  feet. 

144 

Hydraulic  radius  =  *••*•  =  .191  feet. 

i-53 
Substituting  these  values  in  the  equation 


2 


100,000  X  .I9IX  a  r  ,  , 

—7-7  -  *  -  •**  =  9.399  feet  per  second  and 
6.6  X  .191  +  46 

since  q  =  v  X  a  the  discharge  would  be 

9.399  X  .2933  =  2.757  cubic  feet  per  second, 
which  is  approximately  2.82  cubic  feet  per  second.  All 
such  formulas  are  approximate  and  tedious  to  work 
as  trial  depths  must  be  taken.  Thirty-five  per  cent 
must  be  added  to  the  width  of  the  sluice  to  accommodate 
the  water  and  material,  and  35  per  cent  should  be  added 
to  the  depth,  because  a  sluice  should  not  run  more  than 
|  full,  consequently  the  size  obtained  by  the  above 
formula  should  be  increased  70  per  cent. 

Example  (2).  —  It  is  required  to  compute  the  dimen- 
sions  of  a  sluice  to  convey  28.2  cubic  feet  of  water 


SLUICE  BOX  CALCULATIONS  93 

per  second  with  a  grade  of  6  inches  in  1 2  feet,  the  width 
of  the  sluice  to  be  twice  the  depth  of  the  water  flowing 
through  it. 
Solution.  —  Let 

x   =  depth  of  water  in  the  sluice. 
2  x  =  the  width  of  the  sluice. 
4  x  =  the  wet  perimeter. 


=  —  =  the  hydraulic  radius. 

4  x         2 

X2 

—  =  the  hydraulic  radius  squared. 
4 

=  —  =  the  slope  or  grade. 
12  X  12       24 

— ~  =  24£  =  the  mean  velocity. 
2  x2        x2 

Substituting  in  formula 

.-v 


100,000  r2s 
6.6r  +  .46 


14.1   / 

100,000 

4   24 

y  1  00,000  X2 

96 

"        ) 

9  i 

or 
Squaring 

6.6  X 
14.1 

T2 

—  +.46 

2 

3.3  *  +  .46 

./   3125; 

x2 
198.81 

V  9.9  #  + 

3125  x2 

1.92 

x*          9.9^  +  1.92 
Clearing  fractions,      1968.219  x  +  381.7152  =  3125 


94  DEVELOPMENT  OF  PLACER  MINING 

Dividing  by  3125  and  transposing, 

x6  —  .62983  x  =  .1221488. 

Assuming  the  depth  of  the  water  i  foot  for  x  and 
substituting  this  value  in  the  left  hand  number  of  the 
equation, 

i6  -  .62983  X  i  =  i  -  .62983  =  .37017, 
which  is  greater  than  the  second  number  of  the  equation 
and  shows  the  assumed  value  is  too  great.     Trying  a 
value  x  =  .9, 

.9°  -  .62983  X  .9  =  .5314  -  .S66^  =  -  .0354, 
which  is  less  than  the  second  number  of  the  equation, 
hence  .9  is  too  small  for  x  and  the  value  must  be  between 
i  and  .9. 

After  repeated  trials  x  is  found  to  be  equal  to  .94635, 
therefore, 

•946356   -  -62983  X  .94635 
=  .71828333  -.59603962  =  .12224371, 

which  satisfies  the  required   condition,  nearly.     Hence 
x  or  depth  of  sluice  is  .94635  feet  or  11.3562  inches. 

2  x  =  1.8927  feet  or  i  foot,  10.7  inches. 
To  verify  the  foregoing  dimensions  : 
The  wet  perimeter  =  .94635  X2  +  1.8927  =  3.7854  feet. 
Water  area  =  1.8927  X-94635  =  1.79115  sq.  ft. 

Hydraulic  radius      =        ^  —  -  —  —  =  .47317. 

3-7°54 
Substituting  in  the  formula, 


»,    _4/ 

v   —  V 


ioo,ooo  X  -473I7    X      -         ,•      ,  ? 
-  -  -  /0   '  -  «•  =  16.136  feet  per  second 
6.6  X.  473i  7  +.46 

and     16.136  X  1.79  =  28.88  cubic  feet  per  second, 
which  satisfies  the  condition  of  the  problem  approxi- 


SLUICE  BOX  CALCULATIONS  95 

mately.  Thirty-five  per  cent  must  be  added  to  the 
depth  and  width  of  the  box  to  accommodate  the  material 
and  35  per  cent  to  the  depth,  because  the  sluice  should 
not  run  more  than  three  quarters  full. 

With  these  calculations  made  as  follows  the  sluice 
would  have 

1.8927  X  1.35  =  2.565  feet  as  the  width;  and 
.94635  X  1.35  =  1.28    feet  as  the  depth. 

At  large  operations  there  should  be  at  least  two 
sluice  lines,  in  order  that  work  need  not  be  stopped. 
It  is  not  absolutely  necessary  to  have  two  sluice  lines, 
but  it  will  permit  mining  to  be  carried  on  when  one 
sluice  is  out  of  commission,  either  for  repairs  or  for 
cleaning  up.  Where  there  is  plenty  of  water  and  much 
ground  to  be  washed,  the  construction  of  two  or  three 
sluices  may  be  advisable. 

The  material  entering  the  head  of  the  sluice  box  varies 
from  mud  to  large  rocks,  consequently  arrangements  for 
impounding  the  material,  directing  it  to  the  sluice  head, 
and  determining  the  grade  for  its  movement  by  water 
are  considerations  which  the  miner  must  work  out  him- 
self. Usually  a  small  dirt  bank  reservoir  is  constructed 
near  the  working  face  to  form  an  enclosure  that  will  direct 
the  stream  to  the  sluice  head.  The  material  moving  to 
this  latter  point  passes  over  bed  rock  or  an  improvised 
rock  sluice. 

While  sluice  boxes  have  been  operated  on  grades  of  •£§ 
inch  to  the  foot  it  is  better  to  give  them  more  elevation 
where  there  is  heavy  material  and  sand. 

Quartz  sand  travels  slowly  along  the  bottom  of  the 
sluice  and  if  the  current  is  not  stronger  than  that  fur- 


96  DEVELOPMENT  OF   PLACER  MINING 

nished  by  y3g-inch  grade  the  sand  will  lodge  in  the  riffles 
and  prevent  the  gold  entering  them;  further  it  will  form 
a  bed  in  the  sluice.  In  the  latter  case  it  will  be  necessary 
to  keep  spading  the  sand,  which  is  an  extra  cause  of  ex- 
pense besides  being  unsatisfactory.  One  rule  advocated 
by  experienced  men  is  to  give  the  sluice  all  the  grade  possi- 
ble and  at  the  same  time  retain  sufficient  dumping  area  to 
permit  working  the  entire  deposit.  When  this  is  im- 
possible there  are  at  some  places  situations  where  hy- 
draulic elevators  may  be  installed  to  lift  the  material  so 
as  to  obtain  an  auxiliary  sluice  line  to  a  dump,  and  in 
this  way  obtain  the  desired  sluice  grade.  To  prevent 
wear  on  the  sluice  boxes  they  are  lined  on  the  sides  and 
on  the  bottom.  In  this  country  it  is  customary  to  use 
wooden  blocks,  iron  or  steel  sails  to  avoid  the  wear 
on  the  sluice  bottom,  but  the  substitution  of  blocks  of 
granite,  basalt  or  other  hard  stones  may  be  fully  as 
economical  where  readily  obtained;  in  fact  stone  pave- 
ments are  used  where  wooden  blocks  are  difficult  to 
obtain  cheaply. 

In  addition  to  what  has  been  stated  concerning  sluice 
grades  if  it  be  desired  to  calculate  them  the  Chezy  or 
Leslie  equations  may  be  used,  as  they  give  some  ap- 
proximation to  the  quantity  of  water  required  to  set  in 
motion  rounded  stones  or  shingle. 

Leslie's  formula,         i>  =  4  V#. 
Chezy 's  formula,        v  =  5.67  V^g. 

In  these  formulae  v  =  velocity  of  the  water  in  feet  per 
second;  a  =  the  average  diameter  of  the  body  to  be 
moved  in  feet;  g  =  the  specific  gravity  of  the  body. 


DUTY    OF    WATER  97 

The  Leslie  formula  ignores  the  specific  gravity,  but  since 
it  has  been  derived  from  experiments  on  materials  that 
hydraulic  miners  contend  with,  it  is  considered  suffi- 
ciently accurate.  Experience  shows  that  the  quantity 
of  gravel  broken  by  a  stream  of  water  and  sluiced  in  a 
given  interval  of  time  varies  from  i  to  30  cubic  yards 
for  the  same  quantity  of  water  with  the  same  head  of 
pressure;  also  it  has  been  found  that  a  sluice  cut  in  bed- 
rock should  be  given  twice  as  much  grade  as  is  given  to 
a  wooden  sluice  in  order  to  carry  the  same  quantity  of 
material. 

Owing  to  the  wide  variations  in  the  number  of  yards 
of  ground  broken  and  transported  by  a  certain  quantity 
of  water,  the  duty  or  the  number  of  cubic  feet  or  yards 
of  water  used  during  operations  can  only  be  ascertained 
by  close  measurements  over  considerable  periods  of  time. 

This  subject  of  duty  of  water  has  a  bearing  on  the  effi- 
ciency of  the  plant  as  the  following  example  will  explain: 

In  a  period  covered  by  91  days,  321,100  cubic  yards 
of  gravel  were  broken  from  the  bank  and  sluiced  on  a 
grade  of  i  to  37.7  by  the  use  of  14,886,400  cubic  yards  of 
water.  The  ratio  of  water  used  to  earth  removed  was 
therefore  46.36  to  i.  According  to  the  grade  i  part  of 
earth  should  have  been  moved  by  37.7  parts  of  water, 
therefore  the  efficiency  obtained  was  about  81  per  cent 
of  the  theoretical. 


98  DEVELOPMENT   OF   PLACER   MINING 

GRAPHICAL  METHODS  IN  HYDRAULICS.* 

In  this  short  article,  the  application  of  this  method 
of  calculation  to  the  flow  of  water  in  ditches  and  in 
pipes  will  be  discussed  and  a  few  curves  illustrating  the 
method  will  be  printed. 

In  this  country,  in  Germany,  and  in  England,  Gan- 
guillet  and  Kutter's  formula  is  used  almost  exclusively 
to  determine  the  flow  of  water  in  ditches,  while  Bazin's 
new  formula  is  used  exclusively  in  France. 

Either  formula  may  be  reduced  to  the  form  of  the 
well-known  Chezy  formula 

•o  =  c  Vrs  ..............................     i 

in  which  r  =  the  hydraulic  radius  or  hydraulic  mean 

depth. 
s  =  the  sine  of  the  slope  of  the  water  surface 


c  =  a  coefficient. 
Kutter's  formula  gives  for  c  the  values 


n 
c  = 


1.811   .  .  0.00281 

41.65+- 


n 


in  which  n  is  a  coefficient  of  roughness.     The  following 
table  gives  the  values  of  n  usually  used. 
n  =  .009    well-planed    timber,    in   perfect    order    and 
alignment. 

*  L.  C.  Hill  (B.  S.),  E.  E.  (B.  S.),  C.  E. 


COEFFICIENT    OF    ROUGHNESS  99 

n  —  .010  plaster  of  pure  cement;  planed  timber;  glazed 
coated  or  enameled  stoneware  and  iron  pipes; 
glazed  surfaces  of  every  sort  in  perfect  order. 

n  =  .on  plaster  of  cement  with  one-third  sand  in  good 
condition;  iron,  cement  and  terra-cotta  pipes 
well  joined  and  in  best  order. 

n  =  .012  unplaned  timber  when  perfectly  continuous 
on  the  inside  like  straight  flumes. 

n  =  .013  smooth  ashlar  and 'well  laid  brickwork;  ordi- 
nary metal  earthenware  and  stoneware  pipes 
in  good  condition  but  not  new;  cement  and 
terra-cotta  pipes  not  well  laid  nor  in  perfect 
order;  plaster  and  planed  wood  in  imperfect 
and  inferior  condition. 

n  =  .015  second  class  or  rough  faced  brickwork;  well 
dressed  stonework;  foul  and  slightly  tubercu- 
lated  iron,  cement  and  terra-cotta  pipes  with 
imperfect  joints  and  in  bad  order;  canvas 
lining  on  wooden  frames. 

n  =  .017  brickwork,  ashlar  and  stoneware  in  inferior 
condition;  tuberculated  iron  pipes;  rubble  in 
cement  or  plaster  in  good  condition;  fine 
gravel  well  rammed,  one-third  to  two-thirds 
inches  in  diameter;  and  generally  the  mate- 
rials mentioned  for  n  =  .013  when  in  bad 
order  and  condition. 

n  =  .020  rubble  in  cement  in  an  inferior  condition; 
coarse  rubble,  rough  set  in  normal  condition; 
coarse  rubble  set  dry;  ruined  brickwork  and 
masonry;  coarse  gravel  well  rammed,  from 
one  to  one  and  one-half  inches  in  diameter; 


100         DEVELOPMENT   OF   PLACER    MINING 

canals  with  beds  and  banks  of  very  firm  reg- 
ular gravel,  carefully  trimmed  and  rammed 
in  defective  places;  rough  rubble  with  bed 
partially  covered  with  silt  and  mud;  rec- 
tangular wooden  troughs  with  battens  on  the 
inside  two  inches  apart;  trimmed  earth  in 
perfect  order. 
n  =  .0225  canals  in  earth  above  the  average  in  order  and 

regimen. 

n  =  .025     canals  and  rivers  in  earth  of  tolerably  uniform 
cross-section,  slope,  and  direction,  in  moder- 
ately good  order  and  regimen,  and  free  from 
stones  and  weeds. 
n  =  .0275  canals  and  rivers  in  earth  below  the  average 

in  order  and  regimen. 

n  =  .030    canals  and  rivers  in  earth  in  rather  bad  order 
and  regimen,  having  stones  and  weeds  occa- 
sionally, and  obstructed  by  detritus. 
n  =  .035     canals  and  rivers  in  earth  in  bad  order  and 
regimen  and  having  stones  and  weeds  in  great 
quantities. 
n  =  .050    torrents  encumbered  with  detritus. 

In  the  formula  the  value  c  is  made  to  depend  both  on 
r  and  on  s,  as  well  as  on  the  condition  of  the  sides  and 
bottom.  For  rather  small  channels  in  which  the  slope 
is  usually  between  5  =  .0005  and  s  =  .0035,  the  vari- 
ation in  the  value  of  c,  due  to  a  change  in  the  slope  is 
so  small  that  it  may  be  disregarded  in  the  design  of 
ditches  for  power  and  irrigation  when  the  quantities  to 
be  carried  do  not  much  exceed  150  cubic  feet  per  second 
or  are  not  much  less  than  twenty  cubic  feet  per  second. 


GRAPHIC    HYDRAULICS 


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102 


DEVELOPMENT   OF   PLACER   MINING 


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Example  in  the  use  of  the  curves. 

Required  c  when  r  =  1.25  and  n  =  .002.  Starting  at 
a  point  on  the  axis  of  abscissas  where  r  =  1.25,  follow 
up  the  vertical  line  until  the  curve  marked  n  =  .020  is 


GRAPHIC    HYDRAULICS  103 

reached  and  then  follow  the  horizontal  line  to  the  left 
until  the  axis  of  ordinates  is  reached  at  the  point  78, 
which  is  the  value  of  c  for  this  value  of  r. 

The  second  series  of  curves,  Figs.  27,  28  and  29, 
show  the  relation  between  the  hydraulic  radius  r  and 
the  corresponding  values  of  the  mean  velocity  v  for 
various  degrees  of  roughness  and  for  a  number  of  slopes. 
By  means  of  these  curves,  the  hydraulic  radius  to  pro- 
duce any  given  velocity  may  be  quickly  found,  if  the 
slope  is  known.  Any  ditch  having  this  radius  will  have 
for  its  mean  velocity  the  value  of  v  found  and  will  carry 
a  quantity  of  water  equal  to  this  velocity  multiplied  by 
the  area  of  the  cross  section  of  the  ditch. 

Example  in  the  use  of  these  curves. 

Required  the  mean  velocity  in  a  ditch  having  a 
hydraulic  radius  r  =  1.5  and  a  slope  of  i  in  1000  or 
s  =  .001  and  a  roughness  n  =  .025.  Starting  at  a  point 
on  the  axis  of  abscissas  where  r  =  1.5,  follow  up  the 
vertical  line  until  it  intersects  the  curve  marked  5  =  .001, 
and  then  follow  along  the  horizontal  line  to  the  left  until 
the  axis  of  ordinates  is  reached  at  the  point  v  =  2.4, 
which  will  be  the  value  of  v,  which  corresponds  to  this 
value  of  r. 

What  slope  will  it  be  necessary  to  give  a  ditch  having 
a  hydraulic  radius  r  =  1.2,  if  it  is  necessary  for  the  water 
to  have  a  velocity  of  three  feet  per  second  and  the  sides 
and  bottom  are  such  that  n  =  .025?  Starting  at  a  point 
on  the  axis  of  abscissas  where  r  =  1.2,  follow  up  the 
vertical  line  until  it  intersects  a  horizontal  line  drawn 
from  the  point  on  the  axis  of  ordinates  which  corre- 
sponds to  the  velocity  v  =  3  feet  per  second.  This  point 


104 


DEVELOPMENT    OF   PLACER   MINING 


of  intersection  lies  between  the  curves  s  =  .002   and 
5  =  .0025  and  hence  the  required  slope  is  s  =  .0022. 

What  will  be  the  necessary  hydraulic  radius  r  of  a 
ditch  to  have  a  velocity  v  =  2.5  feet  per  second,  if  the 
slope  is  one  and  one-half  feet  in  a  thousand  or  s  =  .0015 


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GRAPHIC    HYDRAULICS 


105 


at  the  point  where  r  =  1.22,  which  is  the  value  of  r 
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The  third  series  of  curves,  Figs.  30  to  35  inclusive, 
give  the  quantity  of  flow  in  second  feet  for  slopes  from 
s  —  .0005  to  5  =  .0030,  in  ditches  having  bottom  widths 


106         DEVELOPMENT   OF   PLACER   MINING 

from  one  to  ten  feet.  The  roughness  used  in  this  series 
is  n  —  .025  and  the  side  slopes  45  degrees.  The  short 
curves  marked  v  =  i.o,  v  =  2.0,  etc.,  intersect  the  main 
curves  at  points  where  the  velocity  in  the  particular 
ditch  is  that  of  the  intersecting  curve.  This  series 
enables  any  problem  within  the  limits  of  the  curves  to 
be  solved  with  great  readiness  and  with  sufficient  accu- 
racy for  all  purposes  of  design.  The  ordinates  are 
quantities  in  second  feet  and  the  abscissas  are  depths 
of  the  water  in  the  ditches  in  feet.  There  is  one  curve 
for  each  bottom  width,  and  values  between  those  given 
in  the  figures  may  be  interpolated  if  necessary. 

Example:  A  ditch  has  a  bottom  width  of  four  feet  and 
a  slope  of  s  =  .001;  what  must  be  the  depth  of  water 
so  that  it  may  carry  50  second  feet  and  what  will  be  the 
velocity  of  the  water  in  it? 

Starting  at  a  point  on  the  axis  of  ordinates  where  q 
has  the  value  50  second  feet,  follow  the  horizontal  line 
to  the  right  until  it  intersects  the  curve  marked  b  =  4 
feet,  then  follow  down  the  vertical  line  until  the  axis 
of  abscissas  is  reached  at  the  point  where  the  depth 
d  =  2.83.  This  gives  the  depth  necessary.  In  order  to 
find  the  velocity,  go  back  to  the  point  of  intersection 
with  the  curve  b  —  4  feet.  This  point  is  between  the 
curve  of  velocities  marked  2.5  and  that  marked  3.0. 
Interpolating,  the  velocity  in  this  ditch  is  about  2.55  feet 
per  second. 

If  the  conditions  are  q  =  60  second  feet,  v  =  2.5  feet 
per  second,  5  =  .001,  and  n  =  .025,  then  both  the  bot- 
tom width  and  the  depth  are  required.  Starting  at  a 
point  on  the  axis  of  ordinates  where  q  =  60  second  feet, 


GRAPHIC    HYDRAULICS 


107 


140 


CURVES 

GIVING  DISCHARGE  IN 

CUBIC  FEET   PER  SECOND 

OF  DITCHES 

n  =  .025  SIDE  SLOPES  1  TO  1 
S  =.0005=2.64  FT.  PER  MILE 


-bO 


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FIG.  30. 


io8         DEVELOPMENT   OF   PLACER   MINING 

follow  the  horizontal  line  to  the  right  until  it  intersects 
the  curve  marked  v  =  2.5.  This  intersection  comes  be- 
tween the  curve  b  =  8  feet  and  that  marked  b  =  g  feet 
and,  by  interpolating,  the  bottom  width  is  8.7  feet. 
From  the  point  of  intersection  of  the  horizontal  line 
with  the  curve  v  =  2.5,  follow  down  the  vertical  line 
until  the  axis  of  abscissas  is  reached  at  the  point  where 
d  =  2.17,  which  is  the  depth  required.  Hence  a  ditch 
to  carry  60  second  feet  under  the  given  conditions  must 
have  a  bottom  width  of  8.7  feet  and  the  water  must 
have  a  depth  of  2.17  feet. 

The  slope  of  a  ditch  is  often  determined  by  the  topog- 
raphy of  the  country.  The  velocity  of  the  ditch 
water  depends  upon  a  number  of  conditions.  It  must 
be  great  enough  to  prevent  the  growth  of  weeds,  and 
it  must  not  be  great  enough  to  cause  erosion  of  the 
canal  bed.  If  silt  and  sand  are  carried  in  suspension, 
the  velocity  must  be  great  enough  to  prevent  their 
deposit.  The  following  table  gives  values  recommended 
by  Ganguillet  and  Kutter,  as  giving  safe  velocities: 


Table  Giving  Safe 

Velocities  in 

Channels. 

Material  of  the  channel. 

Safe  bottom  velo 
in  feet  per  secor 

city      Safe  mean  vel( 
id.          in  feet  per  sect 

Soft  brown  earth  

O.O21C 

O.O33 

-'•"O 

voo 

Soft  loam  

oxo 

0.66 

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•^f.J-^ 

I.OO 

1.  4.  1 

Gravel  

2.OO 

j.  «*f-«- 
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Pebbles 

3.OO 

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O 

o  •yt 

Broken  stone,  flint  

4.  .OO 

^.60 

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o*w 

Conglomerate,  soft  shale. 

5.00 

6-55 

Stratified  rock  . 

6.00 

8.20 

GRAPHIC  HYDRAULICS 


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no         DEVELOPMENT   OF   PLACER   MINING 

A  velocity  of  about  one  foot  per  second  will  in  general 
prevent  the  deposit  of  silt  and  about  two  feet  per  second 
that  of  sand.  Weeds  will  hardly  grow  in  water  flowing 
more  than  two  to  two  and  one-half  feet  per  second.  If 
a  stream  carries  large  quantities  of  sand,  it  is  usually 
necessary  to  provide  means  of  reducing  the  quantity 
carried  in  suspension  as  soon  as  possible  after  it  has 
entered  the  ditch.  This  is  usually  done  by  means  of 
sand  boxes,  as  they  are  called.  These  are  practically 
enlargements  in  the  ditch  or  flume  in  which  the  sand  is 
deposited  from  the  more  slowly  moving  water  and  is 
discharged  at  intervals  by  means  of  special  gates. 

It  must  not  be  forgotten  that  the  velocities  and 
quantities  as  given  in  the  tables  relating  to  ditches  are 
given  for  straight  canals  only.  If  the  curvature  is  great 
these  velocities  and  quantities  will  be  largely  dimin- 
ished, and  allowances  should  be  made  for  such  curva- 
ture, where  possible,  by  slightly  increasing  the  fall. 
Seepage  and  evaporation  are  sources  of  loss  and  vary 
within  wide  limits.  Evaporation  may  reach  an  amount 
equivalent  to  a  lowering  of  the  surface  of  the  entire 
canal  from  six  to  ten  feet  per  year,  most  of  this  loss 
taking  place  during  the  summer  months.  Seepage  may 
be  anything,  but  if  it  exceeds  about  one  per  cent  of  the 
flow  per  mile  of  ditch,  measures  should  usually  at  once 
be  taken  to  reduce  it. 

The  location  of  the  ditch  will  have  much  to  do  with 
both  these  losses,  while  the  character  of  the  soil  will 
usually  affect  the  loss  by  seepage  only.  If  the  canal  be 
carried  upon  the  top  of  ridges  or  along  ground  relatively 
much  higher  than  the  greater  part  of  the  country  through 


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in 


H2         DEVELOPMENT   OF   PLACER   MINING 

which  it  is  built,  the  loss  due  to  evaporation  will  be 
increased  by  exposure  to  wind  and  sun.  A  dry  wind 
blowing  over  the  surface  of  water  causes  usually  a  much 
larger  loss  by  evaporation  than  exposure  to  a  hot  sun, 
while  the  combined  effects  will  of  course  cause  the 
greatest  loss. 

If  the  ditch  is  at  an  elevation  above  the  surrounding 
country,  the  losses  due  to  seepage  are  entirely  uncom- 
pensated  by  any  gains  due  to  drainage  or  seepage  into 
the  canal.  When  the  location  may  be  made  on  side 
hill  slopes  or  in  bottom  lands,  the  seepage  into  the 
ditch  compensates  in  part  for  the  leakage  and  may, 
under  favorable  circumstances,  especially  in  an  old  irri- 
gated country,  cause  a  distinct  gain.  When  a  ditch  is 
first  filled  with  water  the  loss  due  to  seepage  is  always 
largely  in  excess  of  what  may  be  expected  after  a  short 
time.  The  ground  in  the  immediate  vicinity  of  the 
ditch  will  gradually  become  saturated  and  then  the  loss 
will  be  that  strictly  due  to  seepage.  The  flow  from  the 
ditch  can  then  take  place  only  so  fast  as  the  ground 
water  can  flow  away  from  the  canal.  The  movement  of 
ground  water  is  exceedingly  slow,  its  velocity  depending 
upon  the  character  of  the  soil  and  upon  the  slope  of  the 
ground.  In  porous  soils  with  a  heavy  slope  to  the 
country,  the  loss  due  to  seepage  will  be  greatest.  It 
usually  diminishes  as  time  goes  on,  if  the  canal  carries 
silt  or  fine  sand  in  suspension.  Under  some  circum- 
stances, however,  when  the  water  is  very  clear,  this  loss 
may  increase  with  time.  When  the  seepage  from  a 
ditch  is  excessive,  various  expedients  may  be  resorted 
to  to  reduce  or  to  eliminate  completely  this  loss.  These 


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114         DEVELOPMENT   OF   PLACER   MINING 

vary  with  the  conditions  and  with  the  expense  the 
enterprise  will  bear.  Puddling,  paving,  lining  with  con- 
crete (cement  or  asphalt)  are  all  resorted  to. 

In  most  locations,  the  first  method  is  the  cheapest  and 
usually  will  prove  satisfactory.  When  the  velocity  of 
the  water  is  high,  some  better  method  must  be  resorted 
to.  The  cost  varies  between  a  few  cents  per  square 
yard  of  canal  bottom  and  sides  for  the  cheapest  methods 
of  puddling,  to  $2.00  or  more  for  expensive  work  in 
masonry  or  concrete. 

The  greater  cost  per  foot,  of  pipes  carrying  water, 
compared  with  flumes  or  ditches  carrying  the  same 
quantity,  makes  their  design  a  much  more  difficult 
problem.  There  are  a  large  number  of  formulae  which 
have  been  devised  to  represent  the  head  lost  in  friction 
in  a  pipe,  but  nearly  all  involve  the  use  of  a  variable 
coefficient.  This  coefficient  is  usually  made  to  vary 
with  both  the  diameter  of  the  pipe  and  with  the  velocity 
of  the  flow,  usually  increasing  with  both  as  well  as  with 
the  roughness.  In  the  older  formulae,  the  frictional 
resistances  are  made  to  depend  on  the  square  of  the 
velocity  of  flow,  while  the  analysis  of  a  large  number  of 
the  better  experiments  shows  this  resistance  to  vary, 
so  as  to  give  to  this  exponent  values  between  1.75  and 
slightly  above  2.00.  The  lower  values  of  this  exponent 
are  for  the  smoother  surfaces  while  the  higher  values  go 
with  the  rougher  surface.  In  the  more  common  formulae 
at  least,  the  head  lost  in  friction  is  also  made  to  vary 
inversely  as  the  first  power  of  the  hydraulic  radius, 
while  as  before,  analysis  shows  that  it  varies  with  some 
slightly  higher  power.  Lampe,  Tutton,  Flamant,  Findley 


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till       I2J 

FIG.  34. 


n6          DEVELOPMENT   OF   PLACER   MINING 

and  a  number  of  others  have  proposed  formulae  of  the 
general  Chezy  type,  but  with  exponents  for  both  r  and 
s  derived  in  most  cases  from  a  study  of  the  curves 
formed  from  plotting  on  cross-section  paper  the  loga- 
rithms of  v,  r,  and  s  taken  from  the  best  experiments. 
The  general  form  of  the  equation  is: 

v  =  crxsv    .................  3 

Reduced  to  logarithmic  form  this  is 

Log  v  =  log  c  +  x  log  r  +  y  log  s  ........  4 

For  any  particular  pipe  r  is  a  constant  and  if  in  this 
pipe  Si  corresponds  to  some  special  value  of  vi,  then 

Log  vi  =  log  c  +  x  log  r  +  y  log  si  .......  5 

and  hence 

Log  vi  -  log  v  =  y  (log  si  -  log  s)  .......  6 

which  is  the  equation  of  a  straight  line  with  logv  and 
log  s  as  co-ordinates.  From  this,  the  exponent  of  s 

-  log  v  —  log  ^1 
log  s  -  log  si  ' 

If  from  any  set  of  experiments,  values  of  s  and  v  be  taken 
and  their  corresponding  logarithms  plotted,  the  straight 
line  resulting  will  be  inclined  to  the  axis  of  velocities 
at  an  angle  whose  tangent  is  y  or 


_  g 

log  s  -  ' 


If  other  values  be  taken  from  experiments  made  on 
pipes  of  different  diameters  but  of  the  same  roughness, 
each  set  on  the  same  diameter  will  give  a  new  straight 


GRAPHIC    HYDRAULICS 


117 


i-o 


CURVES 

GIVING   DISCHARGE  IN 

CUBIC  FEET   PER  SECOND 

OF  DITCHES 

n  =  .025  SIDE  SLOPES   1  TO  1 
S=.  0030  =  15.  84  FT.   PER  MILE 


•120 


140 


1  0 


-90 


40 


--3 


er-m-Keet 


FIG.  35. 


u8          DEVELOPMENT   OF   PLACER   MINING 

line  inclined  to  the  velocity  axis  at  the  same  angle 
tani  y.  It  is  nearly  impossible  to  obtain  a  series  of 
experiments  made  on  pipes  all  of  exactly  the  same 
degree  of  roughness,  so  that  it  is  hardly  to  be  expected 
that  all  these  lines  will  have,  in  practice,  precisely  the 
same  inclination,  but  if  good  judgment  has  been  shown 
in  selecting  the  experiments,  the  lines  will  all  have 
nearly  the  same  inclination  and  the  average  angle  may 
be  used  without  appreciable  error. 
When  in  the  formula 

v  =  crxsv 9 

5  =  1  then 

v  —  crx 10 

and 

Log  v  =  log  c  +  x  log  r ii 

If  r\  corresponds  to  some  particular  value  of  r  then 

Logfli  =  logc  +  xlogri 12 

and  therefore 

Logy  -  logz>i  =  x  (logr  - 


and  hence 

logr-logri*  ' 

This  is  the  equation  of  a  straight  line,  the  co-ordinates 
of  which  are  log  v  and  log  r,  where  log  v  has  the  par- 
ticular value  for  each  pipe  given  when  s  =  i  or  log  v  =  o. 
This  is  the  particular  value  given  in  the  first  set  of  curves 
by  the  intersection  of  each  line  with  the  axis  of  veloci- 
ties. The  tangent  of  the  angle  this  line  makes  with  the 
axis  of  velocities  will  be  the  value  of  x  found  by  sub- 
stituting in  equation  (14). 


GRAPHIC  HYDRAULICS 


119 


The  value  of  log  c  is  the  value  of  log  v,  when  r  and  5 
are  both  unity,  or  log  v  =  log  c  and  v  =  c  for  this  value. 
Hence  the  number  corresponding  to  the  logarithm  of 


og  of 


S  fin  1  Log 


LAP  SEAM  RIVETED  WROUGHT  IRON  PIPES 
COATED  WITH  ASPHALT.     STOVE  PIPE  JOINTS 


FIG.  36. 

v  at  the  point  where  this  last  line  intersects  the  axis  of 
velocities  will  be  the  value  of  the  coefficient  c  in  the 
formula  and  will  apply  to  this  roughness  only.  If  for 
a  particular  series  of  experiments,  the  roughness  is 


120         DEVELOPMENT   OF   PLACER   MINING 

nearly  the  same  (perhaps  near  enough  to  make  all  of 
the  lines  of  the  first  plotting  parallel)  but  yet  differing 
a  little,  there  may  be  more  than  one  line  for  the  next 
plotting.  These  lines  will  be  parallel  or  nearly  so,  but 
each  one  will  give  a  different  value  for  c. 

In  this  manner  the  coefficients  and  exponents  in  the 
general  formula 

v  =  crxsv 15 

have  been  determined  for  many  kinds  of  pipes  and 
ditches,  for  this  formula  is  as  applicable  to  ditches  as  to 
pipes. 

The  values  obtained  by  Tutton  and  Flamant  from 
the  analysis  of  a  very  large  number  of  the  best  experi- 
ments, both  here  and  abroad,  have  been  used  in  plotting 
the  curves  giving  the  loss  of  head  in  pipes  per  1000  feet, 
when  carrying  various  quantities  of  water. 

Curves  are  given  for  but  two  kinds  of  pipes,  and 
should  be  used  in  the  design  of  a  pipe  line  only  when 
the  pipe  is  one  of  these,  and  not  otherwise,  except 
as  a  rough  check  on  the  correctness  of  the  numerical 
work.  If  the  line  is  a  long  one  and  the  pipe  is  forced 
by  the  topography  of  the  country  to  come  near  to  the 
hydraulic  grade  line,  the  results  given  by  the  curves 
should  be  most  carefully  checked  to  prevent  the  pipe 
being  laid  above  this  grade  line.  Lack  of  attention  to 
this  essential  detail  has  been,  in  many  cases,  the  cause 
of  endless  trouble  until  the  pipe  was  again  relaid  so  as 
to  be  below  the  hydraulic  grade  line.  Tutton  obtained 
for  wood  stave  pipe  the  value 

v  =  125  r86*-61 16 


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37. 


122          DEVELOPMENT   OF   PLACER   MINING 

If  for  v  is  substituted  its  value  in  terms  of  q,  for  5  its 

value  -  and  for  r  its  value  -  ,  and  the  equation  be  then 
I  4 

solved  for  /?,  the  head  lost  in  friction  in  the  pipe 

01.961 

h  =  .0007465  I  ~~^ 17 

In  these  curves  the  value  of  h  is  the  head  lost  per  1000 
feet  and  for  this  the  formula  becomes 

,1.961 

,.18 


Another  set  of  curves  giving  the  horse-power  required 
to  drive  various  quantities  of  water  through  wooden 
stave  pipes  1000  feet  long  is  given  in  Fig.  38.  The 
pipes  are  supposed  to  have  their  ends  upon  the  same 
level  and  to  be  practically  straight.  The  loss  is  then 
due  to  frictional  resistances  only. 

If  h  is  the  head  lost  in  friction  in  the  pipe  per  1000 
feet  of  length,  then  the  horse-power  required  will  be 

TT  wqh 

Horse-power  =  -*- 10 

550 

where  w  is  the.  weight  of  a  cubic  foot  of  water,  about 
62.4  pounds,  and  where  q  is  the  number  of  cubic  feet 
flowing  in  the  pipe  and  550  is  the  number  of  foot  pounds 
in  one  h.p.  second.  Substituting  these  values, 

Horse-power  =  .1134  hq 20 

Substituting  for  h  its  value  from  equation  (18), 

^2.961 

H.p.  lost  per  1000  feet  of  pipe  =  .08465    -     .  .  .21 


1*8 -i 

5g*  i 

£2* 
>  t 

a  UJK- 
D  tnu. 

O^o 


JJO 


FIG.  38. 


123 


124         DEVELOPMENT   OF   PLACER   MINING 

Both  this  set  of  curves  and  the  set  giving  the  loss  of 
head  per  1000  feet  of  pipe  in  friction  show  how  rapidly 
the  losses  increase  after  the  quantity  for  each  pipe 
reaches  a  certain  value.  This  emphasizes  the  necessity 
of  keeping  the  velocity  low,  thus  restricting  the  total 
loss  and  at  the  same  time  permitting,  at  a  small  addi- 
tional loss,  the  pipe  to  carry,  if  required,  a  slight  increase 
in  amount.  For  example:  if  the  quantity  carried  by  a 
1 2 -inch  pipe  is  3  cubic  feet  per  second  and  this  is  in- 
creased to  4  cubic  feet  per  second,  the  horse-power  lost 
per  thousand  feet  of  pipe  will  be  changed  from  2.2  to 
5.25  horse-power,  or  by  3.05  horse-power.  If  the  initial 
quantity  was  7  cubic  feet  per  second  and  this  was  in- 
creased to  8  cubic  feet,  the  horse-power  lost  would 
change  from  27  to  40,  a  change  of  13  horse-power,  over 
four  times  as  much. 

These  curves  are  plotted  so  that  the  abscissas  are  in 
each  figure  the  quantities  of  water  in  cubic  feet  per 
second,  and  the  ordinates  are,  in  Fig.  37,  the  losses 
of  head  per  1000  feet  of  pipe,  and  in  Fig.  38  the  horse- 
power lost  per  1000  feet  of  pipe. 

Example: 

What  must  be  the  diameter  of  a  wooden  stave  pipe 
5000  feet  long  so  that  it  may  carry  5  cubic  feet  per 
second  with  a  loss  of  head  due  to  friction  of  20  feet? 
The  loss  due  to  friction  per  1000  feet  will  be  ^  of  20 
or  4  feet.  Starting  at  a  point  on  the  axis  of  abscissas 
where  q  =  4,  follow  up  the  ordinate  at  that  point  until 
it  intersects  the  abscissa  drawn  through  the  point  on 
the  axis  corresponding  to  4  feet.  This  point  lies  on  the 
1 6-inch  curve  and  the  diameter  of  the  pipe  is  16  inches. 


GRAPHIC    HYDRAULICS  125 

What  will  be  the  loss  of  head  due  to  friction  in  a  pipe 
4550  feet  long  14  inches  in  diameter  when  carrying 
5  cubic  feet  per  second?  Starting  at  a  point  on  the  axis 
of  abscissas  where  q  -  5,  follow  up  the  ordinate  at  that 
point  until  it  intersects  the  curve  d  =  14  inches.  From 
this  point  follow  along  the  abscissa  until  the  axis  of 
ordinates  is  reached  at  the  point  where  h  =  7.8  feet. 
This  gives  the  loss  per  1000  feet.  Multiplying  this  loss 
by  the  number  of  thousand  feet,  4.55,  gives  35.49  feet 
as  the  total  head  lost  in  friction  in  the  whole  pipe. 

From  Fig.  38  the  horse-power  lost  in  friction  is  found 
in  the  same  manner  from  the  curves. 

Example: 

The  length  of  the  pipe  is  4550  feet,  its  diameter  is 
14  inches,  what  will  be  the  horse-power  lost  in  the  pipe 
due  to  friction  when  it  is  carrying  5  cubic  feet  per  second? 

Starting  at  a  point  on  the  axis  of  abscissas  where 
q  =  5,  follow  up  the  ordinate  at  that  point  until  it 
intersects  the  curve  d  =  14  inches.  From  this  point 
follow  along  the  abscissa  until  it  intersects  the  axis  of 
ordinates  at  the  point  where  horse-power  lost  =  4.45. 
This  is  the  loss  per  thousand  feet.  Multiplying  this  by 
the  length  of  the  pipe  in  thousands  of  feet,  4.55,  gives 
20.25  as  the  horse-power  lost  by  friction  in  the  whole 
pipe. 

The  horse-power  which  may  be  delivered  by  any  pipe 
carrying  water  from  one  elevation  to  another  is  equal 
to  the  theoretical  energy  of  the  water  in  horse-power  less 
the  horse-power  lost  in  friction  in  the  pipe.  Strictly 
speaking,  this  loss  should  include  that  due  to  entrance, 
to  bends,  etc.,  and  in  the  nozzle,  if  one  be  used.  If  the 


126          DEVELOPMENT   OF   PLACER   MINING 

pipe  be  a  long  one,  these  losses  are  insignificant  com- 
pared with  those  due  to  friction  in  the  pipe  and  may 
be  neglected. 

Let  h  =  the  difference  in  elevation  in  feet  between 
the  ends  of  the  pipe. 

Then 

Theoretical  horse-power  =  -*-  ....  . .  22 

550 

=  -1134  hq 23 

The  horse-power  which  can  be  delivered  equals 
Theoretical  horse-power  —  Horse-power  lost  in  friction. 
Hence  for  wooden  stave  pipe 

02.961 

H.p.  delivered  =  .1134  hq  —  .000084651  fVjg  .  .  .24 

In  this  equation  the  second  term  in  the  right-hand 
member  is  the  horse-power  lost  in  friction  in  a  wooden 
stave  pipe  i  foot  long. 

This  equation  shows  that  the  available  horse-power 
increases  to  a  maximum  and  then  diminishes  to  zero 
when 

02.961 

.1134  hq  =  .00008465  /ijr^jj 25 

The  set  of  curves  plotted  from  equation  (25)  shows 
the  general  character  of  this  variation  of  available  horse- 
power with  the  discharge.  It  can  not,  of  course,  be 
used  with  any  other  length  of  pipe  than  2000  feet  nor 
other  difference  in  elevation  between  the  ends  than  100 
feet.  An  inspection  of  these  curves  shows  that  the  same 
power  may  be  obtajned  from  any  pipe  by  allowing  two 
quantities  of  water  to  flow.  They  show,  also,  that  with 


- 
(3  OOz 

«-V2 

UJ  0-  U.- 


Bffll 


V<tl[ 


128         DEVELOPMENT  OF  PLACER  MINING 

an  unlimited  water  supply  there  is  a  certain  quantity 
which,  flowing  in  the  pipe,  will  give  the  maximum  horse- 
power. This  quantity  is  roughly  about  55  per  cent  of 
the  maximum  flow  which  may  be  obtained  from  the 
pipe.  When  the  pipe  is  giving  this  maximum  horse- 
power, it  has,  however,  an  efficiency  of  approximately 
65  per  cent. 

Example: 

What  will  be  the  diameter  of  a  pipe  to  deliver  100 
horse-power,  if  the  length  of  the  pipe  is  2000  feet,  the 
difference  in  elevation  between  the  two  ends  is  100  feet 
and  the  quantity  of  water  available  is  10  cubic  feet  per 
second?  Starting  at  a  point  on  the  axis  of  abscissas 
where  q  =  10,  follow  up  the  ordinate  at  that  point  until 
it  intersects  the  abscissa  drawn  from  the  point  on  the 
horse-power  axis  where  h.p.  =  100.  This  point  of  in- 
tersection lies  between  the  curve  d  =  18  inches  and  that 
marked  d  =  20  inches.  To  be  on  the  safe  side  the 
larger  pipe  should  be  used.  Hence  a  20-inch  pipe  is 
required. 

Example: 

The  diameter  of  a  pipe  is  18  inches,  its  length  is  2000 
feet  and  the  difference  in  elevation  between  the  two  ends 
is  100  feet.  What  will  be  the  available  horse-power  at 
the  nozzle,  if  the  pipe  is  carrying  n  cubic  feet  per 
second?  What  will  be  the  available  horse-power  when 
carrying  16.4  cubic  feet  per  second? 

From  the  point  on  the  axis  of  abscissas  where  q  =  n 
follow  up  the  ordinate  until  the  curve  d  =  18  inches  is 
reached.  From  this  point  follow  the  abscissa  to  the  left 
until  the  axis  of  horse-power  is  reached  at  the  point 


2 
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jaaj  ur  p^an 


130         DEVELOPMENT  OF   PLACER  MINING 

where  the  available  horse-power  is  100,  which  is  the 
value  required. 

In  the  same  way  the  horse-power  available,  when  a 
quantity  q  =  16.4  cubic  feet  per  second  is  flowing  in  the 
same  pipe,  is  found  to  be  100  horse-power. 

Where  the  conditions  are  different  from  those  for 
which  these  curves  were  plotted,  Fig.  37  (which  gives 
the  horse-power  lost  in  friction  in  pipes  1000  feet  long) 
will  enable  a  solution  to  be  made  with  ease  and  rapidity. 

Example:  Let  h  =  250  feet  and  let  q  =  4  cubic  feet 
per  second.  Find  the  diameter  of  a  pipe  3500  feet  long 
to  deliver  100  horse-power  if  the  losses  be  confined  to 
those  due  to  friction  in  the  pipe  only. 

Then  the 

Theoretical  horse-power  =  .1134X250X4 

=  ii34. 

The  difference  between  this  value  and  the  horse-power 
to  be  delivered  by  the  pipe  is  what  is  lost  in  friction,  or 

Horse-power  lost  in  friction  =  113.4  —  100.0  =  13.4. 

The  loss  per  1000  feet  will  then  be  this  loss  divided 
by  the  number  of  thousands  of  feet  in  the  pipe  or 


=  3.83  horse-power. 

O'J 

Referring  to  Fig.  38,  start  at  the  point  on  the 
discharge  axis  where  q  =  4  and  follow  up  the  ordinate 
until  it  intersects  the  abscissa  drawn  from  the  point 
where  the  horse-power  lost  equals  3.83.  The  curve 
nearest  this  point  of  intersection  is  one  for  a  pipe  13 


GRAPHIC    HYDRAULICS  131 

inches  in  diameter  and  is  the  diameter  of  the  pipe 
necessary  to  deliver  100  horse-power  under  the  required 
conditions. 

As  the  theoretical  horse-power  available  was  113.4 
and  only  100  horse-power  can  be  delivered  by  this  pipe, 
its  efficiency  will  be 


Efficiency  =  =  .883. 

1134 

In  the  present  article,  no  curves  are  given  for  ordi- 
nary riveted  steel  pipes.  The  number  of  experiments 
so  far  available  and  at  the  same  time  reliable  is  so 
limited  as  to  make  it  inadvisable  to  attempt  to  formu- 
late the  flow  in  this  class  of  pipe.  The  carrying  ca- 
pacity of  this  kind  of  pipe  does  not  seem  to  increase 
as  rapidly  with  increase  in  diameter  as  might  have  been 
expected.  This  is  probably  due  to  the  effect  of  the 
larger  rivets  and  the  increased  thickness  of  the  lap  joints 
as  the  diameter  of  the  pipe  increases. 

An  increase  in  pressure  under  which  a  pipe  of  this 
kind  is  used  will  cause  a  reduction  in  the  flow,  by  in- 
creasing the  size  of  rivets  and  the  thickness  of  the  plates 
and  hence  the  obstruction  offered  to  the  flow  by  the 
joints.  In  riveted  pipes  the  losses  are  due  to  at  least 
three  causes: 

1.  That  due  to  sudden  enlargement  at  alternate  joints. 

2.  That  due  to  sudden  contraction  at  alternate  joints. 

3.  That  due  to  increase  in  the  roughness  and  the  in- 

direct losses  due  to  eddy  currents  set  up  by  the 
rivets. 
For  the  thinner  wrought  iron  pipes  used  extensively 


132          DEVELOPMENT   OF   PLACER   MINING 

in  Colorado  and  California,  the  values  given  by  the 
curves  for  coated  cast  iron  pipes  will  usually  be  safe. 
The  rivet  heads  are  small  and  very  smooth  when  coated 
and  the  sudden  changes  in  diameter,  owing  to  the 
thinness  of  the  pipe,  are  inconsiderable.  This  kind  of 
pipe  is  always  coated  so  that  the  surface  friction  is 
probably  lower  than  that  of  cast  iron,  the  obstructions 
offered  by  the  rivet  heads  and  the  joints  making  its 
surface  practically  the  same  as  that  of  cast  iron. 

The  surface  of  most  pipes  deteriorates  with  use,  and 
the  discharge,  other  conditions  remaining  unchanged, 
decreases.  If  the  flow  is  maintained  constant,  the  head 
lost  in  friction  will  increase.  This  increase  depends 
upon  the  material  of  which  the  pipe  is  constructed,  its 
coating,  the  quality  of  the  water,  and  the  care  used  in 
laying  to  protect  the  coating  and  to  preserve  the  align- 
ment. 

The  effect  produced  is  usually  much  greater  in  small 
pipes  than  in  those  of  large  diameter.  The  same  abso- 
lute amount  of  accretions  produces  two  effects,  a  greatly 
increased  roughness  of  interior  and  an  actual  reduction 
in  the  area  of  the  pipe.  This  reduction  of  area  may 
vary  between  practically  nothing  and  that  due  to  a 
deposit  of  one  or  more  inches  in  thickness.  A  deposit 
one  inch  thick  would  reduce  the  area  of  a  6-inch  pipe 
about  55  per  cent,  while  it  would  change  the  area  of  a 
1 6-inch  pipe  by  but  27  per  cent. 

The  writer  has  seen  2 -inch  cast  iron  pipes  not  over  ten 
years  old  practically  closed  by  a  peculiar  rust-like  de- 
posit. When  this  deposit  was  removed,  the  covering 
was  usually  unimpaired. 


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FIG.  41. 


134         DEVELOPMENT  OF   PLACER  MINING 


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FIG.  42. 


GRAPHIC    HYDRAULICS  135 

The  flow  in  old  pipes  is  greatly  reduced,  but  in  a  way 
impossible  to  formulate  with  any  certainty.  Pipes  well 
coated  and  carefully  laid,  carrying  water  reasonably 
clear  and  free  from  deleterious  substances,  may  show 
scarcely  any  loss  in  capacity  after  ten  years  of  use, 
while  pipes  with  an  inferior  coating,  carrying  dirty 
water  or  water  carrying  in  solution  alkalies  or  acids, 
may  in  that  time  show  a  loss  of  70  per  cent  or  more. 

In  designing  a  pipe  line  to  carry  a  given  quantity 
of  water,  this  change  in  capacity  with  time  should  be 
taken  into  account,  ^and  the  diameter  of  the  pipe  line 
be  based  on  a  future  delivery  of  the  required  amount. 
In  some  enterprises,  where  the  pipe  may  be  in  use  for 
a  few  years  only  and  first  cost  is  of  great  importance, 
it  will  be  safe  to  put  in  a  pipe  figured  to  carry  water 
under  present  conditions,  making  no  allowances  for  de- 
terioration unless  the  water  is  known  to  be  very  bad. 

On  the  four  vertical  lines  (Fig.  42)  are  shown  four 
quantities,  discharge,  diameter,  loss  of  head  or  slope, 
and  velocity.  The  intersection  of  any  straight  line  with 
these  four  vertical  lines  indicates  corresponding  values  of 
these  four  quantities;  so  that  any  two  being  given,  the 
other  two  are  determined  by  the  application  of  a  straight 
edge.  This  plate  was  taken  from  an  article  by  Prof. 
C.  B.  Stewart. 

Example: 

The  discharge  of  3000  gallons  per  minute  through  a 
12-inch  pipe  gives  a  velocity  of  8.8  feet  per  second. 


CHAPTER  IV. 

RIFFLES,   UNDERCURRENTS,    AND    DUMPS. 

Riffles  were  mentioned  under  rockers  and  are  merely 
traps  intended  to  stop  gold  from  moving  along  the  sluice 
bottom.  For  coarse  gold  they  are  very  effective,  but 
for  gold  containing  impurities,  gold  attached  to  rock, 
leaf  gold,  flour  gold,  or  gold  attached  to  black  sands 
they  are  not  satisfactory  savers,  unless  aided  by  under- 
currents and  mercury. 

There  are  many  kinds  of  riffles,  some  of  which  are 
patented,  consequently  it  is  necessary  to  use  judgment 
in  their  selection,  as  there  would  not  be  this  number  if  it 
were  possible  to  save  all  the  gold  in  places.  A  placer 
miner  after  long  experience  in  a  certain  mine  stated  that 
he  did  not  know  how  much  gold  was  in  his  dirt,  but  he 
knew  it  was  worth  60  cents  per  yard  gross  to  him,  for 
that  was  his  average  saving.  Some  placers  that  have 
assayed  rich  in  gold  have  proved  flat  failures  as  business 
propositions  owing  to  the  physical  condition  of  the  gold, 
and  the  writer  has  had  several  experiences  where  the 
value  of  a  sluicing  proposition  has  been  based  upon  the 
fire  assay  of  the  concentrates  that  included  black  sands. 
Sluicing  is  a  purely  mechanical  operation,  and  only  free 
gold  enters  into  a  proposition  of  this  kind,  therefore  one 
must  know  within  reasonable  limits  what  the  physical 
condition  of  the  gold  is  before  attempting  work.  Coarse 
or  nugget  gold  will  travel  but  a  short  distance  even  if 

136 


RIFFLES  137 

there  are  no  riffles,  provided  there  is  an  uneven  place  for 
it  to  lodge,  however  a  stone  moving  along  will  dis- 
lodge it  and  then  it  moves  to  the  next  uneven  place.  To 
prevent  this  riffles  are  needed  as  otherwise  the  gold  will 
eventually  reach  the  end  of  the  sluice. 

Flour  gold  is  very  fine  and  will  be  held  in  suspension 
in  muddy  water;  leaf  gold  will  float  along  the  bottom  of 
a  sluice  unless  it  can  be  stopped  in  some  way,  and  gold 
attached  to  black  sand  or  rock  will  be  lost. 

It  is  no  wonder  then  that  there  should  be  a  variety  of 
riffles,  and  all  based  upon  their  ability  to  save  gold. 
Some  prefer  transverse  riffles  that  have  proved  effectual 
in  saving  gold  in  operations  with  which  they  were  once 
connected;  others  prefer  longitudinal  riffles  for  the  same 
reason,  however  this  rule  of  thumb  will  not  suffice  and 
as  previously  stated  the  operators  must  use  judgment. 
The  writer  has  saved  gold  in  a  longitudinal  riffle  that 
seemingly  would  not  remain  in  a  transverse  riffle,  how- 
ever he  found  that  by  a  combination  of  both  he  could 
save  more  than  with  either  separately. 

In  some  cases,  mercury  will  not  save  gold,  in  other 
cases  it  will  do  so,  therefore  mercury  should  be  used  in 
conjunction  with  riffles  when  the  latter  prove  ineffectual 
in  saving  gold  that  mercury  will  attack. 

Coarse  gold  does  not  need  mercury,  while  fine  clean 
gold  can  only  be  saved  by  its  use,  when  however  mercury 
is  discarded  in  undercurrents  there  is  a  mistake  made 
for  it  has  been  proved  in  rich  placers  like  those  of  Little 
Creek  on  the  Seward  Peninsula  that  mercury  saved  fine 
gold,  that  it  is  customary  to  run  into  the  tailings.  When 
gold  is  encased  in  the  oxides  or  sulphides  of  other  metals, 


138     RIFFLES,   UNDERCURRENTS,  AND  DUMPS 

the  combination  prevents  amalgamation,  besides  lessens 
the  specific  gravity  of  gold  to  such  an  extent  it  floats 
away  in  the  current.  This  kind  of  gold  material  can 
not  be  saved  except  by  concentrating  the  sands,  or  griding 
them  so  as  to  expose  the  gold,  and  then  giving  them 
a  lixiviation  treatment. 

Pole  Riffles  made  of  saplings  split  and  nailed  to  the 
sluice-box  floor  are  the  crudest  of  riffles,  and  yet  they 
are  useful  when  better  riffles  can  not  readily  be  obtained. 
The  saplings  are  placed  transversely  or  longitudinally  to 
suit  the  ideas  of  the  operator.  Where  there  is  much 
clay  in  the  ground  nails  are  driven  in  the  poles  so  that 
they  will  project  a  half  inch.  This  breaks  up  the  clay 
in  a  measure,  and  thus  frees  the  gold. 

Board  Riffles  are  shown  in  Fig.  43  to  be  longitudinal 
strips  nailed  to  scantlings,  that  are  as  long  as  the  sluice 
is  wide  inside.  This  riffle  forms  a  false  floor  to  the 


FIG.  43. 

sluice  and  prevents  that  wearing,  at  the  same  time  the 
gold  that  passes  in  between  two  boards  is  held  by  the 
scantlings.  Such  riffles  are  readily  raised  when  it  is 
desired  to  clean  up  or  remove  the  gold  and  as  readily 
replaced.  They  are  not  as  good  for  fine  as  for  coarse 
gold,  and  if  two  consecutive  riffles  are  placed  so  the 
spaces  between  the  boards  are  in  line,  the  gold  may 
travel  over  the  boards  instead  of  going  between  them. 


RIFFLES 


Slot  Riffles.  —  Wooden  riffles  constructed  as  shown  in 
Fig.  44,  are  termed  slot  riffles,  the  slots  being  about  2 
inches  wide,  8  inches  long  and  }  inch  deep.  Mercury 


FIG.  44. 

is  placed  in  each  slot.  These  riffles  can  be  arranged  so 
that  the  longer  dimensions  of  the  slots  come  either  across 
or  lengthwise  of  the  sluice.  The  slope  for  such  riffles 
should  not  exceed  8  inches  in  12  feet,  otherwise  fine  gold 
will  wash  over  the  mercury.  In  all  riffles  intended  to 
save  fine  gold,  the  mercury  used  should  be  charged  with 
at  least  some  gold  as  mercury  containing  amalgam  is 
better  in  holding  fine  gold  than  pure  mercury.  Riffles 
should  never  be  charged  full,  as  they  are  subject  to  a  loss 
of  mercury  under  the  most  favorable  conditions,  and  the 
loss  will  be  increased  if  the  riffles  are  kept  too  full.  As 
sand  moves  over  a  sluice  bottom,  and  comes  to  the  mer- 
cury it  passes  over  the  mercury  owing  to  the  latters 
specific  gravity.  Fine  gold  will  also  be  moved  over  the 
mercury  unless  it  is  in  proper  physical  condition  for 
amalgamation,  and  it  may  require  several  riffles  before 
the  gold  is  finally  captured.  The  action  of  mercury  is 
not  to  absorb  gold  and  form  amalgam  at  once,  but  to 
gradually  dissolve  it;  therefore,  float  gold,  and  what  is 


140        RIFFLES,  UNDERCURRENTS,  AND  DUMPS 

termed  spongy  gold,  is  not  easily  caught  by  mercury  on 
account  of  its  lightness  or  a  coating  of  some  kind  of 
material.  The  specific  gravity  of  mercury  being  at 
60°  Fahr.  13.58,  and  native  gold  19.3,  or  if  containing 
silver  15.6  to  19.3,  it  follows  that  the  gold  will  sink  into 
the  mercury  bath,  while  sand,  with  a  specific  gravity  of 
2.63  to  3,  will  not.  But  mercury  is  not  necessary  to 
catch  the  heavier  particles  of  gold,  which  would  lodge 
anyway,  but  is  useful  in  saving  the  fine  gold,  if  it  can  be 
held  in  contact  with  the  mercury  a  sufficient  time  to  allow 
it  to  be  dissolved. 

After  the  formation  of  amalgam,  which  is  brittle  com- 
pared with  mercury,  according  to  the  amount  of  material 
it  has  absorbed,  there  is  danger  of  loss  by  its  floating 
away,  and  this  means  a  loss  of  mercury  and  gold. 

Frequently  free  mercury  escapes  from  the  riffles  and 
is  lost,  owing  to  it  being  subjected  to  shock  from  stones 
that  roll  along  the  floor  and  splash  into  the  mercury  trap. 
To  prevent  this  the  trap  orifices  should  be  made  narrow 
so  that  large  stones  can  not  enter,  and  small  stones  can 
not  enter  at  high  speed.  Stones  less  than  one  half  inch 
in  diameter  have  spattered  fresh  mercury,  when  allowed 
to  splash  into  riffles.  The  kind  of  riffle  to  adopt  will 
depend  upon  the  size  of  the  operation  and  those  so  far 
mentioned  would  not  be  suitable  for  a  large  hydraulic 
proposition.  Mr.  A.  J.  Bowie  considers  that  where 
coarse  material  is  washed  "block  riffles "  have  advan- 
tages over  any  other. 

1.  Because  they  make  a  cross-riffle. 

2.  They  are  inexpensive  and  durable. 

3.  They  are  convenient  to  tear  up,  clean,  and  replace 


BLOCK   RIFFLES  141 

The  blocks  for  riffles  may  be  square  or  round,  and  from 
8  to  13  inches  high.  The  squared  blocks  are  placed  in 
rows  across  the  bottom  of  the  sluice  and  separated  trans- 
versely by  strips  of  i-inch  boards,  to  furnish  a  mercury 
trap  and  hold  the  blocks  in  position.  The  strips  are 
nailed  to  the  blocks,  and  the  blocks  are  wedged  to  the 
sides  of  the  sluice  box  as  an  additional  precaution  to 
prevent  their  moving.  The  longitudinal  fibers  of  the 
blocks  are  placed  upwards  in 
order  that  wear  and  tear  will 
be  lessened,  and  the  fibers 
may  assist  it  arresting  the 
movement  of  the  gold.  The 
blocks  are  also  arranged  so 
that  they  will  not  have  their 
joints  in  the  same  line,  or 
are  laid  as  a  mason  lays  FlG  45 

bricks     by    breaking    joints. 

Fig.  45  shows  a  sluice  box  with  round  block  riffles. 
This  style  of  riffle  is  as  effective  in  saving  gold  as  the 
square  block  riffle,  and  is  also  used  where  the  material 
washed  is  coarse.  The  blocks  should  be  of  hard  wood, 
and  held  in  place  by  strips  of  boards  nailed  to  them  or 
to  the  floor.  In  some  cases  cobble  stones  are  used  at 
the  head  of  a  sluice  box  where  the  impact  of  the  material 
is  the  greatest,  as  blocks  wear  much  faster  in  this 
place  than  in  the  sluice  proper.  The  objection  to  round 
blocks  is,  that  they  are  difficult  to  obtain  of  the  same 
diameters  and  are  therefore  difficult  to  lay  and  fasten  in 
the  sluice,  however  this  objection  is  not  sufficient  to 
prevent  their  use. 


142     RIFFLES,  UNDERCURRENTS,  AND   DUMPS 

Stone  Riffles  have  been  used  where  coarse  material 
was  to  be  washed.  Stones  over  the  size  of  ones  fist,  and 
from  that  to  stones  weighing  100  pounds  are  considered 
coarse  material.  In  large  operations  there  is  no  time 
to  assort  the  material  and  everything  that  the  water 
brings  to  the  sluice  is  passed  through.  While  this  is  not 
good  practice,  often  times  it  can  not  be  avoided,  par- 
ticularly in  hydraulicking.  Sluices  to  handle  material  of 
this  kind  must  be  lined  on  the  sides  and  floor,  as  in  Fig. 
14,  to  prevent  their  being  destroyed  before  the  season  is 
over. 

Riffles  for  saving  fine  gold  are  constructed  so  as  to 
conform  to  the  ideas  of  the  operator,  however  his  ideas 
are  frequently  modified  to  conform  with  the  locality  and 
means  at  command.  If  sluices  are  long,  and  riffles  and 
amalgam  traps  are  used,  it  may  be  necessary  to  patrol 
the  line  for  the  purpose  of  keeping  watch  over  the  riffles, 
and  seeing  that  they  do  not  become  choked,  do  not  leak, 
and  finally  that  amalgam  is  not  stolen. 

Iron  Riffles.  —  Iron  rails  are  used  to  some  extent  as 
riffles.  When  s'o  used  they  are  laid  lengthwise  of  the 
sluice  with  the  flange  either  up  or  down.  They  are 
fastened  together  in  such  a  way  that  the  ends  will  not 
curl  up,  and  they  are  also  spaced  with  blocks  between 
them. 

The  objections  to  rail  riffles  are,  their  great  weight, 
opportunities  they  offer  to  gold  to  ride  the  rail  flanges, 
and  their  cost.  There  are  conditions,  no  doubt, 
that  would  favor  such  riffles,  for  instance  where  the 
rocks  are  not  water  rounded,  and  where  there  is 
excessive  wear  on  block  riffles.  A  riffle  used  to  some 


IRON  RIFFLES  143 

extent  in  the  Seward  Peninsula  l  is  shown  in  Fig.  46. 
It  is  a  light  iron  casting  that  can  be  readily  handled. 
The  slots  are  placed  either  longitudinally  or  transversely, 
although  the  longitudinal  position  relative  to  the  sluice 
is  considered  to  be  most  effective. 


Scale  in  Inches 
OL23456789101112 

FIG.  46. 


The  subject  of  iron  riffles  would  be  incomplete  with- 
out a  description  of  the  Risdon  Iron  Company's  patent 
riffle,  a  section  of  which  is  shown  in  Fig.  47. 

The  object  of  such  riffles  is  to  create  dead  water  under 
them  and  save  such  fine  gold  as  mercury  will  not  readily 
hold,  and  rusty  gold  that  mercury  will  not  attack.  Inci- 
dentally, in  accomplishing  this  purpose  they  do  away 

1  C.  W.  Purington,  Mining  Magazine,  February,  1905. 


144       RIFFLES,  UNDERCURRENTS  AND  DUMPS 


with  the  use  of  mercury,  and  hence  loss  of  quicksilver 
and  amalgam;  further,  they  are  more  easily  handled  and 
cleaned  up  than  the  ordinary  riffle.  The  amalgam 


FIG.  47- 

retort  is  thereby  abolished,  and  the  gold  is  recovered 
purer,  and  commands  a  better  price. 

The  riffles  are  made  of  angle  iron  in  sections,  for  any 
width  of  sluice  desired.  Each  section  is  2  feet  in  length, 
so  that  the  sections  can  be  readily  removed  for  cleaning 
up.  The  angle  irons  are  fastened  at  each  side  to  the 
box,  and  are  spaced  so  that  any  gold  passing  down  the 
sluice  along  the  bottom  may  fall  into  the  spaces  thus 
created.  As  no  water  comes  in  except  from  the  open- 
ings or  spaces,  the  water  under  the  riffles  is  dead,  allowing 
fine  gold  to  settle  and  remain  in  the  trap  until  removed 
at  "clean-up." 

Float  Gold.  — Float  gold  is  either  in  thin  scales  or  in 
such  small  light  particles  that  it  is  termed  flour  gold.  Mer- 
cury will  amalgamate  such  gold  if  the  mercury  and  gold 
are  in  proper  condition  for  alloying.  If  the  mercury  is 
sickened  by  impurities  in  the  dirt  such  as  arsenic,  sul- 
phide of  antimony,  manganese,  etc.,  it  acts  so  sluggishly 


UNDERCURRENTS  145 

that  fine  gold  will  move  over  it.  Float  gold  will  be 
buoyed  up  by  muddy  water,  particularly  water  contain- 
ing much  clay,  or  talc. 

Talc  seems  to  form  a  sort  of  scum  that  prevents  the 


FIG.  48. 

mercury  from  attacking  the  gold  until  it  has  been 
washed  off.  Clay  acts  similarly,  particularly  if  it  contains 
much  iron  oxide.  Spongy  gold  is  fine  gold  containing 
pores  into  which  clay  or  other  material  has  filtered  to 
such  an  extent  as  to  greatly  decrease  its  specific  gravity, 
and  such  gold  will  float  over  mercury,  where  solid  grains 
will  sink  through. 

Undercurrents  are  introduced  in  sluice  lines  to  relieve 


146     RIFFLES,  UNDERCURRENTS,  AND  DUMPS 

the  main  sluice  of  coarse  material  and  save  fine  gold. 
For  this  purpose  a  grizzly  made  up  of  iron  bars,  set  on 
edge,  one  inch  apart  lengthwise  of  the  sluice,  is  used  for 
a  sluice  bottom,  see  Fig.  48. 

The  finer  material  passes  through  the  bars,  while  the 
coarser  material  remains  on  the  bars.  Below  the  bars 
is  a  coarse  iron  screen  which  checks  the  momentum  of 
the  coarse  material  and  affords  any  gold  that  passes  over 
the  bars  an  opportunity  to  reach  the  undercurrent. 
The  undercurrent  is  a  shallow  wooden  box,  from  four  to 
ten  times  the  width  of  the  sluice  and  high  enough  to 
contain  the  material  washed  into  it.  It  is  paved  with 
either  wood  or  stone  in  such  a  manner  as  to  stand  wear 
and  serve  as  riffles.  The  water  and  material  that  flows 
swiftly  in  the  sluice  is  suddenly  spread  over  a  very  much 
larger  area  and  this  gives  the  gold  an  opportunity  to 
settle.  After  the  material  enters  the  undercurrent  it  is 
spread  over  the  entire  box  width  by  the  riffles,  although 
the  inclination  of  the  undercurrent  is  considerably  more 
than  that  of  the  sluice. 

The  undercurrent  is  gradually  narrowed  towards  the 
discharge  end,  to  conform  with  the  width  of  the  sluice 
into  which  it  discharges.  In  some  cases  the  large  stones 
left  on  the  grizzly  are  not  permitted  to  enter  the  sluice 
again,  but  this  is  not  always  practicable  on  account  of 
dumping  ground.  If  the  water  is  to  transport  the  large 
stones  the  entire  quantity  can  not  enter  the  undercurrent, 
and  sufficient  must  pass  the  grizzly  to  carry  the  stones 
down  the  sluice  after  they  are  removed  from  the  screen 
bars. 

Undercurrents   are   at   times   great   gold   savers,    for 


UNDERCURRENTS  147 

example  with  a  sluice  5  feet  wide,  and  an  undercurrent 
20  feet  wide,  there  was  a  saving  of  20  per  cent  of  the 
gold,  and  upon  making  the  undercurrent  30  feet  wide  an 
additional  7  per  cent  was  saved.  This  was  accomplished 
without  increasing  the  length  of  the  grizzly,  and  shows 
the  advantage  of  suddenly  decreasing  the  velocity  and 
depth  of  the  current.  There  may  be  several  under- 
currents in  a  sluice  line,  depending  on  the  quantity  of 
fine  gold  and  the  clay  in  the  dirt  washed.  The  grade 
given  undercurrents  varies  from  12  inches  in  12  feet,  to 
1 8  inches  in  12  feet.  A  short  undercurrent  20  feet  in 
length  should  have  a  steeper  grade  than  one  40  feet  long, 
the  reason  being  that  the  material  will  flow  in  a  thinner 
stream  on  a  steep  grade.  The  riffles  in  the  undercurrent 
will  exert  considerable  influence  on  the  grade,  and  one 
can  only  determine  their  action  after  experimenting. 
Fig.  49  is  an  undercurrent  used  on  a  dredge  in  Atlin, 
B.  C.1  The  grizzly  has  J-inch  spaces  between  the  bars, 
a  practice  to  be  followed  where  the  table  is  but  n  feet 
7  inches  long. 

The  method  of  distributing  the  material  passing 
through  bars  as  well  as  the  mercury  traps  is  shown 
in  section.  The  practice  of  using  amalgam  plates  in 
such  cases  is  questionable,  since  they  will  be  scoured  in 
all  probability  even  should  a  large  proportion  of  the 
material  be  less  than  J-inch  diameter. 

This  undercurrent  is  shown  here  as  an  explanation  of 
%.e  Hungarian  riffle. 

Hungarian  Riffles.  The  riffle  shown  in  Fig.  49  con- 
3ists  of  a  series  of  gouges  made  in  a  2-inch  plank,  so 

1  Report  of  Minister  _of  Mines,  1904. 


148        RIFFLES,  UNDERCURRENTS,  AND  DUMPS 

staggered  that  they  will  cover  the  width  of  the  sluice 
bottom.  This  form  of  riffle  is  a  favorite  on  dredges  and 
in  some  small  sluice  mines;  it  is  not  however  superior 
in  any  way  to  other  riffles,  and  must  not  be  used  where 
there  are  coarse  stones,  if  the  operator  is  anxious  to  save 
mercury.  Mercury  is  usually  placed  in  each  depression. 
A  somewhat  similar  riffle  is  made  by  boring  2-inch  holes, 
J-inch  deep  in  2-inch  planks,  and  staggering  them  so 
that  no  part  of  the  current  shall  escape  passing  over 
some  of  the  holes.  Mercury  is  usually  placed  in  these 
holes  to  catch  and  retain  the  gold.  Stones  lodge  in 
them  and  as  they  are  washed  out  by  other  stones  strik- 
ing them  there  is  generally  a  loss  of  quicksilver  and 
amalgam. 

The  Dump  is  one  of  the  requisites  of  a  sluicing  propo- 
sition. The  lack  of  dumping  ground  is  often  a  hin- 
drance to  hydraulic  mining  and  in  California  it  prevents 
many  places  from  being  worked.  In  the  early  days  of 
hydraulicking  thousands  of  tons  of  earth  were  washed 
daily  into  rivers  that  became  clogged  and  changed  their 
channels.  The  material  broken  down  occupied  a  larger 
space  than  in  the  original  bank,  and  spread  over  the 
valleys,  particularly  the  valley  of  the  Sacramento  River 
in  California.  Fertile  farm  land  was  destroyed,  making 
it  necessary  for  the  government  to  stop  hydraulicking, 
until  some  method  could  be  devised  to  conserve  the  farm 
lands  and  at  the  same  time  permit  mining.  The  con- 
struction of  " debris  dams"  by  appropriations  from  the 
government  and  state  has  only  partially  restored  the 
industry.  Where  there  is  a  large  river  into  which  the 
debris  may  be  sluiced  by  gravity  without  damaging 


§0 

Q  m 

z 

<  2 

I-  -I 


o  DC 

.DC  O 

Ul  _l 
Q 


V 


149 


150     RIFFLES,   UNDERCURRENTS,  AND   DUMPS 

farm  lands,  hydraulicking  and  sluicing  is  still  carried  on, 
not  only  in  California  but  in  other  localities. 

The  lack  of  dumping  ground  for  tailings  will  often 
necessitate  a  lengthening  of  the  sluice. 

In  Fig.  50  are  shown  a  number  of  tributaries  to  the 
original  sluice.  These  provide  a  wider  area  for  the  dis- 
posal of  the  tailings,  and  were  necessary  owing  to  the  flat- 
ness of  the  dumping  ground. 

In  some  cases,  as  for  instance  at  Breckenridge,  Colo- 
rado, it  is  possible  to  use  hydraulic  elevators  and  thus 
obtain  a  fall  sufficient  to  sluice  the  waste  material  to  a 


,  jgi 

FIG.  50. 

suitable  dumping  ground.  To  use  an  hydraulic  eleva- 
tor there  is  needed  a  large  supply  of  water.  This  is 
lacking  in  some  cases,  and  then  to  dispose  of  the  debris 
other  methods  are  adopted.  The  plan  adopted  at 


DUMPING    GROUND  151 

placers  where  both  water  for  hydraulicking  and  fall  for 
dumping  ground  was  lacking  is  illustrated  in  Figs.  76 
and  89.  In  cases  where  water  for  elevators  was  lacking, 
a  good  line  of  elevator  buckets  might  be  found  service- 
able in  disposing  of  tailing.  They  would  require  power, 
and  this  might  be  furnished  from  the  sluice. 


CHAPTER  V. 

WATER    SUPPLY. 

WHERE  placer  mining  operations  are  to  be  carried  on 
by  hydraulicking,  the  most  important  factor  to  be  deter- 
mined is  the  quantity  of  water  that  can  be  depended 
upon.  In  some  cases  water  has  been  conducted  through 
ditches,  flumes,  pipes,  and  tunnels  for  50  miles  and  in 
one  case  100  miles.  This  of  course  requires  an  im- 
mense capital  and  a  thorough  survey  of  all  the  watersheds 
throughout  the  length  of  the  ditch.  If  the  ditch  can  be 
connected  with  a  large  river  or  lake  without  too  great 
expense,  the  placer  miner  will  have  an  ideal  water 
supply.  This  however  is  possible  only  occasionally, 
and  for  the  most  part  the  supply  for  placer  operations 
must  be  obtained  from  streams  supplied  by  melting 
snows  and  rains.  While  this  supply  may  be  in  excess 
of  the  miner's  needs  at  certain  seasons  it  may  be  so  scant 
in  the  summer  months  that  operations  must  cease.  It 
is  necessary  in  order  to  ascertain  what  definite  supply 
can  be  depended  upon  the  season  through,  to  examine 
the  records  of  snow  and  rain  fall,  and  to  locate  places 
where  reservoirs  may  be  established  as  feeders  in  times 
of  dry  weather. 

To  carry  the  survey  out  properly,  reliable  data  must 
be  obtained  in  regard  to  the  average  flow  from  creeks 

and  springs  and  the  area  drained  by  them.     In  selecting 

152 


ABSORPTION  AND  EVAPORATION  153 

the  site  for  a  storage  reservoir  me  following  information 
is  to  be  obtained. 

1.  The  elevation  above  the  mine,  so  that  a  sufficient 
pressure  will  be  assured  for  operating  the  giants  and 
elevators. 

2.  The    watershed    feeding    the    reservoir,    and    the 
water  that  may  be  depended  upon. 

3.  The  formation  and  character  of  the  ground  with 
reference  to  the  absorption  and  leakage  that  might  occur. 

Absorption  and  Evaporation.  —  The  most  desirable 
ground  for  a  reservoir  site  is  one  of  compact  rock,  like 
granite,  gneiss,  or  slate.  .  Porous  rocks,  like  sandstone 
and  limestone,  are  not  so  desirable,  on  account  of  their 
absorptive  qualities.  Steep,  denuded  slopes  are  best 
watersheds,  as  then  but  little  water  will  sink  into  the 
ground  and  the  remainder  will  go  into  the  reservoir. 
The  longest  slope  will  furnish  the  largest  available 
quantity  of  water  provided  vegetation  does  not  cause 
too  much  absorption.  Bowie  states  that  at  the  Bowman 
reservoir,  in  California,  75  per  cent  of  the  total  rainfall 
and  snowfall  (reduced  to  rain)  is  stored. 

A  reservoir  should  hold  a  supply  capable  of  meeting 
the  maximum  demands.  The  area  of  the  reservoir  is 
determined  by  surveys  and  a  table  made  showing  its 
contents  for  every  foot  of  depth,  so  that  the  amount  of 
water  available  can  always  be  known.  The  Bowman 
reservior  contains  about  1,050,000,000  cubic  feet  of 
water.  The  catchment  area  or  watershed  is  28.94 
square  miles.  The  cost  of  the  reservoir  and  dams  was 
$246,707.51.  Beside  the  main  reservoir,  all  mines 
should  have  auxiliary  reservoirs  which  although  com- 


154 


ABSORPTION  AND  EVAPORATION 


155 


paratively  small  are  adapted  for  short  runs.  These 
are  for  the  sake  of  insuring  a  supply  in  case  of  accidents 
to  any  part  of  the  main  supply  ditch  above  them.  An 
allowance  must  be  made  for  leakage  and  evaporation, 
in  the  ditch  line,  and  this  loss  in  cubic  feet  per  second 
per  mile  may  be  approximately  estimated  from  the 
formula. 

Ma 
v    X  5280 

in  which  M  is  a  coefficient  that  varies  from  3  to  20 
according  to  the  climate. 

Storage  reservoirs  are  particularly  necessary  where 
the  water  supply  is  from  mountain  streams  which  have 
a  tendency  to  slack  off  in  water  during  the  summer 
months.  The  erection  of  retaining  dams  for  such  reser- 
voirs is  part  of  the  ditch  system. 

The  primary  object  of  dams  is  to  retain  water;  they 
therefore  should  be  water  tight.  Dams  must  have  firm 
foundations  to  prevent  their  sinking,  and  have  their 
bases  sufficiently  wide  to  prevent  their  being  moved 
down  stream  by  the  pressure  of  the  water  against  them. 


p  P 


FIG.  51. 


FIG.  52. 


It  will  be  necessary  to  increase  the   base  of  a  dam  in 
width  as  the  dam  increases  in  height. 


WATER  SUPPLY 


Fig.  51  shows  an  incorrect  method  of  building  a  dam 
wherever  the  volume  of  water  is  variable.  The  pres- 
sure, P,  of  the  water  increases  with  depth,  and  exerts  a 
pressure,  P',  which  tends  to  slide  the  dam  off  its  base. 
If  constructed  as  in  Fig.  52,  the  dam  will  be  more  stable 
and  resist  the  water  pressure  at  its  base,  for  the  weight 
now  acts  in  part  to  keep  the  dam  in  position,  conse- 
quently is  opposed  to  the  pressure,  P',  which  acts  to  push 
the  dam  outward. 

Masonry  dams  are  expensive,  but  masonry  is  neces- 
sary at  least  at  the  sides  of  any  reservoir  which  is  to 
contain  any  amount  of  water.  The  center  may  be 
crib-work,  weighted  down  with  stones,  puddled  clay, 
etc. 

Crib  Dams.  —  The  crib  dam,  Fig.  53,  is  made  of 
logs,  bolted  and  spiked  together.  The  ties,  P,  are 


FIG.  53. 

notched  in  diamond-shape,  with  a  section  of  the  log 
forming  a  collar.  They  are  longest  at  the  bottom  of 
the  crib,  to  be  weighted  down;  they  are  also  spiked  to 
the  log  below  them  through  the  collar. 

The  face  logs  are  notched  to  receive  the  diamond- 
shaped  collar  of  the  ties.     The  face  logs  should  have 


157 


i 

•H. 

^ 

•I 


MINER'S  INCH 


159 


the  joints  broken,  and  the  ties  should  all  be  one  above 
the  other.  This  structure  may  be  given  a  batter  on  the 
outside  or  be  reinforced  by  an  embankment  of  stone. 
The  weighting  down  of  the  ties  should  proceed  with, 
the  building  up.  Care  should  be  used  to  puddle  the 
structure  to  prevent  leakage.  Large  stones  if  laid  with 
some  system  next  to  the  face  inside  the  crib  will  prolong 
its  life  considerably.  The  ties  will  not  rot  fast,  and 
the  face  will  last  many  years,  even  when  rotted  consid- 
erably, if  such  a  system  be  followed. 

Miner's  Inch.  —  The  miner's  inch,  up  to  the  year 
1905,  was  very  confusing,  as  each  ditch  company  in 
California  at  least  had  a  water  inch  of  its  own.  The 
miner's  inch  in  California  is  now  1.5  cubic  feet  per 
minute,  or  11.25  gallons  per  minute.  For  calculations 
and  reference  the  following  table  will  be  found  useful. 

A  flow  of  one  miner's  inch  of  water  is  equal  to  the  supply  of  — 


Gallons. 

Cubic  Feet. 

Per  second    

1871? 

02  s 

Per  minute    

II    2^ 

T   e 

Per  hour    

J.A'O 

67? 

QO   OO 

Per  day      

y/>' 

IO2OO. 

2l6o. 

Or,  a  flow  of  one  cubic  foot, 

Per  second  equals  40  miner's  inches; 
Per  minute  equals  §  miner's  inch; 
Per  hour  equals  .0110  +  miner's  inch. 

The  most  common  measurement  for  a  miner's  inch  is 
through  an  aperture  2  inches  high  and  whatever  length 
is  required,  over  or  through  a  plank  ij  inches  thick,  as 
shown  in  the  Fig.  54.  The  lower  edge  of  the  aperture 
is  2  inches  above  the  bottom  of  the  measuring  box,  and 


160  WATER  SUPPLY 

the  top  plank  5  inches  above  the  aperture,  thus  at  the 
center  of  the  stream  flowing  out  there  is  a  6-inch  pres- 
sure of  water.  Each  square  iinch  of  this  opening  will 
discharge  ij  cubic  feet,  or  nj  gallons  of  water  per  min- 
ute, a  quantity  that  represents  a  miner's  inch.  If  the 
slide  be  moved  out  i  inch  the  aperture  for  discharge  will 


FIG.  54. 

be  2  square  inches  and  the  flow  of  water  3  cubic  feet  per 
minute,  or  2  miner's  inches. 

Weir  Measurement.  —  To  form  a  weir  and  measure 
a  small  stream  place  a  board  or  plank  notched,  as 
shown  in  Fig.  55,  at  some  point  in  a  stream,  where  it 
will  dam  the  water  and  form  a  pond  above  it.  The 
notch  in  the  plank  should  be  twice  the  depth  for  a 
small  quantity  of  water  and  longer  in  proportion  if  a 
large  quantity  of  water  is  to  be  measured. 

The  edges  of  the  notch  should  be  beveled  toward  the 
intake  side,  as  shown.  The  overfall  below  the  notch 
should  not  be  less  than  twice  its  depth;  that  is,  if  the 
notch  is  6  inches  deep  the  overfall  should  be  12  inches. 
In  the  pond,  about  three  feet  or  more  above  the  weir, 
drive  a  stake,  and  then  partially  obstruct  the  water  until 
it  rises  to  the  bottom  of  the  notch,  and  mark  the  stake 


WEIR   MEASUREMENTS 


161 


at  this  level.  Then  complete  the  weir  so  that  all  water 
in  stream  will  go  over  the  notch,  and  make  another 
mark  at  this  level  on  the  stake.  The  distance  between 
the  marks  on  the  stake,  measured  in  inches,  is  the 
theoretical  depth  of  flow. 


FIG.  55. 

To  find  the  discharge  over  a  weir  of  this  description 
in  cubic  feet  per  second : 1 
Let       h  =  head  in  feet. 

b   =  the  length  of  the  overfall  in  feet. 

c   =  constant  number  3.33. 

Q  =  discharge  in  cubic  feet  per  second. 
Then  Q  =  Vtf  XbX  3.33. 

Example.  —  How  many  cubic  feet  per  second  will 
flow  over  a  weir  4  feet  long,  0.64  feet  deep,  measured  as 
at  h  or  on  the  stake,  with  the  constant  number  3.33  ? 

Solution.  —  Q  =  V.64  X.64  X-64  =  V. 262144  = 
.512  X  4  X  3.33  =  6.82  cubic  feet  per  second,  or  51.15 
gallons  per  second. 

To  facilitate  matters  for  the  engineer,  tables  of  weir 

1  Trautwinc. 


162  WATER  SUPPLY 

measurements  have  .been  made.  The  table  on  page  408 
gives  the  cubic  feet  of  water  per  minute  which  will  flow 
over  a  weir  i  inch  wide  and  from  J  to  20 J  inches  deep. 
For  example,  suppose  the  weir  to  be  60  inches  long 
and  the  depth  of  the  water  on  it  to  be  6f  inches.  Follow 
down  the  column  marked  inches  on  the  left  until  6  is 
reached;  follow  across  the  table  on  the  line  with  6  until 
f  is  reached,  when  6.44  is  found.  Multiply  this  latter 
number  by  60,  which  gives  386.40,  the  number  of  cubic 
feet  passing  per  minute. 

Stream  Measurement.  —  Weirs  are  only  adapted  to  the 
measurement  of  water  flowing  through  brooks,  hence  larger 
streams  are  measured  in  some  other  way.  To  measure 
approximately  a  stream  by  the  current  and  cross-section: 

Measure  the  depth  of  the  water  at  from  6  to  12  points 
across  the  stream,  at  equal  distances  apart.  Add  these 
depths  in  feet  together  and  divide  by  the  number  of 
measurements  made  to  obtain  the  average  depth  of  the 
stream,  and  this  quotient  multiplied  by  the  width  of  the 
stream  will  give  the  depth  of  its  average  cross-section. 

The  velocity  of  the  stream  is  now  found  by  measuring 
ico  feet  along  the  bank;  marking  both  ends  of  the  line, 
and  throwing  a  float  into  the  stream  a  short  distance 
above  the  upper  mark.  The  time  consumed  by  the  float 
in  passing  the  distance  of  100  feet  is  the  recorded  velocity. 
This  operation  should  be  repeated  several  times,  in  order 
to  determine  the  average  velocity  of  the  current. 

One-half  dozen  floats  thrown  into  the  stream  together 
and  timed  from  the  first  one  passing  the  upstream  mark 
to  the  first  one  passing  the  goal  will  give  a  closer  average 
time. 


FLUMES  163 

Dividing  this  distance  by  the  average  time  found  for 
covering  it  gives  the  velocity  in  feet  per  minute  at  the 
surface  of  the  stream.  The  surface  water  moves  swifter 
than  the  water  at  the  bottom  or  sides  of  the  stream,  the 
difference  being  about  8  per  cent,  but  for  approximate 
calculations  this  need  not  be  considered. 

Flumes.  —  Where  the  life  of  a  mine  is  not  more  than 
ten  years,  and  timber  is  cheap,  flumes  may  be  adopted 
to  advantage  for  conducting  the  water  from  the  reservoir 
to  the  pressure  box. 

Flumes  are  probably  cheaper  to  construct  than 
ditches,  and  their  repair  is  less.  The  calculation  for 
the  carrying  capacity,  etc.,  of  flumes  is  the  same  as  for 
sluice  boxes,  and  need  not  be  repeated.  In  most  ditch 
lines  flumes  must  be  used  for  a  portion  of  the  distance, 
there  being  no  other  feasible  method  of  overcoming  cer- 
tain difficulties  in  the  construction  of  the  ditch.  It  is 
better  if  possible  to  carry  a  ditch  around  the  head  of  a 
canon,  than  to  cross  the  canon  with  a  flume  on  a  trestle 
or  siphon  pipes.  While  as  a  rule  it  is  better  to  avoid 
flumes,  there  are  situations  where  they  can  not  'be 
avoided,  in  fact  a  flume  was  bracketed  to  a  cliff,  118 
feet  above  the  bed  of  a  ravine  and  232  feet  below  the 
top  of  a  cliff  in  California. 

Where  rock  is  to  be  excavated,  or  where  porous  ground 
is  met,  or  where  chasms  are  to  be  crossed,  recourse  must 
be  had  to  the  box  flume. 

In  building  a  flume,  nothing  smaller  than  ij-inch 
plank,  tongued  and  grooved,  should  be  used,  and  these 
joints  should  be  white-leaded  and  well  driven  home. 
The  sides  should  be  made  of  the  same  material,  dry  pine 


164  WATER  SUPPLY 

or  spruce  —  the  latter  is  preferable  —  and  be  thoroughly 
fastened  to  the  posts.  The  sills  should  not  be  over  4 
feet  apart,  should  project  18  inches  beyond  the  outside 
of  the  box  to  take  braces,  and  in  cases  where  there  are 
tunnels  or  trestles  they  should  project  far  enough  to 
receive  a  1 2-inch  plank  for  a  walk,  in  order  that  the 
flume  may  be  examined;  in  other  situations  the 
plank  placed  along  the  cap  pieces  will  be  sufficient.  In 
laying  the  lining,  care  should  be  taken  to  break  joints 
and  the  lining  should  be  first-class  lumber,  free  from 
knots. 

The  grade  given  the  flume  will  have  some  bearing 
on  its  size  —  the  steeper  the  grade  the  more  water  the 
flume  will  pass  for  a  given  area;  this  will  allow  con- 
siderable decrease  in  area  over  the  area  of  the  ditch, 
and  consequent  economy,  wherever  the  whole  grade 
from  the  source  to  the  outlet  may  permit  of  an  increase. 
The  flume  grade  may  be  increased  from  ditch  grade  of 
0.25  per  cent  or  13.2  feet  per  mile  to  0.50  or  0.75  per 
cent. 

It  is  not  always  customary  to  employ  side  braces 
for  the  flume;  they  should,  however,  be  used  in  certain 
situations.  Wherever  the  flume  crosses  a  ravine  on 
trestles,  braces  will  make  the  whole  structure  more 
rigid  against  wind,  even  when  the  trestles  are  anchored 
by  wire  ropes;  again,  on  the  side  of  a  hill  or  cliff,  where 
the  flume  runs  full  at  one  time  and  half  full  at  another, 
braces  will  tend  in  a  measure  to  prevent  warping,  espec- 
ially wherever  the  sun's  rays  strike  the  flume. 

In  this  connection  it  is  well  to  allow  a  little  water  to 
run  over  the  bottom  of  a  flume  at  all  times,  to  keep  the 


166  WATER  SUPPLY 

joints  tight,  as  the  change  from  dry  to  wet  conditions 
invariably  causes  leakage. 

The  size  of  a  flume  will  decide  the  timber  to  be  used 
in  its  construction  —  that  is,  a  flume  2  X  ij  feet  will 
not  require  as  heavy  lumber  as  one  3X3  feet  in  sec- 
tional area,  except  for  lining. 

The  sills,  posts,  and  cap  pieces  of  a  flume  should  not 
be  over  four  feet  from  center  to  center,  and  if  three  feet 
between  centers  it  will  be  more  rigid. 

In  building  flumes  it  is  not  altogether  what  they  bear 
in  weight,  for  there  are  other  factors,  such  as  leakage 
and  warping,  which  must  be  guarded  against,  and  with 
sills  far  apart  the  latter  material  elements  in  the  problem 
have  greater  play.  In  the  construction  of  a  flume  3X3 
feet  the  following  timber  would  be  required  for  100  feet, 
the  sills,  caps,  and  posts  being  placed  three  feet  between 
centers: 

34  sills,  3  X  4  X  6'  1 1"  =     235  feet,  2  inches. 

68  posts,  3  X  4  X  3'  2"  =    215    "    4      " 

34  caps,  3  X  4  X  4'  3"  =     144    "    6       " 

68  braces,  3X2X3'  =    102    "    o      " 

54  lining  plank,  12  X  ij  X  15'  =  1215    "    o       " 

9  lining  plank,  12  X  i J  X  10'  =     135    "    o       " 


Per  hundred  feet,  2047  feet,  o  inches. 

Per  mile,  52.8  times,  108,082. 

Note.  —  The  above  bill  does  not  include  walk  or 
battens;  add  11,780  feet  for  i  X  3"  battens  and  19,720 
feet  for  ij  X  12"  walking  plank  per  mile. 

The  lumber  per  mile  of  flume  does  not  include  stringers 


FLUME  CALCULATIONS  167 

or  blocks,  which  must  be  placed  lengthwise  of  the  flume 
on  trestles;  in  this  connection  it  must  be  borne  in  mind 
that  the  foundation  for  a  flume  must  be  solid  and  level, 
especially  under  each  sill.  The  usual  size  for  stringers 
in  a  3  X  3-foot  flume  is  4  X  6  inches,  but  this  size  must 
be  determined  by  the  distance  between  bents  in  the 
trestle,  since  the  stringers,  as  well  as  supporting  the 
weight  of  the  flume  and  water,  tie  the  trestle  bents. 
With  bents  12  feet  between  centers  the  stringers  should 
be  6  X  12  inches  for  this  area  of  flume. 

The  sills  should  be  notched  for  the  posts;  the  caps 
should  be  mortised  for  tenent  at  the  top  of  the  posts, 
and  secured  by  J-inch  wooden  pins.  The  general 
practice  is  to  make  notches  for  both  caps  and  sills, 
using  spikes  to  hold  them. 

Where  curves  are  necessary  in  the  flume  the  outer 
side  of  the  flume  must  be  raised,  to  correspond  to  the 
degree  of  curvature;  J-inch  elevation  from  the  lower 
side  for  every  degree  of  curvature  will  be  sufficient.  This 
elevation  should  commence  on  the  straight  line  or  tan- 
gent of  the  ditch  before  it  meets  the  curve,  as  this  will 
tend  to  equalize  the  flow.  The  elevation  should  be 
gradual  and  reach  its  height  at  the  center  of  the  curve, 
and  as  gradually  recede,  until  the  flume  again  becomes 
straight,  the  object  being  to  change  the  motion  with  the 
least  friction  possible  and  avoid  the  water  pouring  over 
the  side  of  the  flume  at  the  center  of  the  curve.  Where- 
ever  curves  are  met  the  sills  and  posts  are  set  closer,  and 
greater  care  is  to  be  observed  in  placing  the  lining. 

At  times  it  becomes  necessary  to  run  along  the  side 
of  a  cliff;  this  is  accomplished  by  drilling  holes  in  the 


168 


SIDE-HILL  FLUMES 


169 


cliff  and  putting  in  iron  brackets,  upon  which  the  string- 
ers for  the  flume  rest.  The  brackets  curve  upward 
parallel  to  the  posts,  and  are  fastened  by  anchors  to  the 
cliff  above  the  flume.  In  San  Juan  County,  Colorado, 
flumes  are  carried  some  distance  in  this  manner.  Flumes 
should  have  3  X  i-inch  pine  battens  over  the  floor- 
seams  to  prevent  wear,  and  should  be  provided  with 
gates  at  intervals,  to  allow  water  to  be  drawn  off ;  further, 
where  snow  or  dirt  is  likely  to  slide  into  them  from  the 
mountain  side,  they  should  be  covered  with  sheds. 

A  common  method  of  constructing  flumes,  and  placing 
them  on  half-bents  is  shown  in  Fig.  56. 

This  method  was  probably  introduced  first  by  the 
North  Bloomfield  Mining  Company  in  California,  in 


FIG.  56. 

their  ditch  line  between  Eureka  and  Milton  dam.     The 
slope  of  the  rock  in  some  places  was  such  that  to  con- 


170  WATER  SUPPLY 

tinue  the  ditch  would  call  for  an  enormous  outlay  of 
money,  and  as  it  was,  the  foundations  for  the  5.3  miles 
of  flumes  cost  $18,920.  It  will  be  observed  that  the 
posts  are  dapted  into  the  sills  and  caps  of  the  flume,  and 
that  the  stringers  are  also  dapted  for  the  bent  cap.  For 
a  3  X  4-foot  flume,  lined  with  i  J-inch  planks  and  bat- 
tened where  the  planks  join  the  caps  and  legs,  are 
8  X  8-inch  timbers,  and  the  braces  are  3  X  8-inch 
timbers.  The  cap  must  rest  firmly  on  the  foundation, 
and  a  proper  faced  hitch  must  be  cut  for  the  leg.  In 
addition  to  these  precautions  holes  are  drilled  in  the 
rock  and  the  timbers  spiked  to  the  rock. 

The  stringers  are  8  X  lo-inch  timbers  dapted  for 
the  bent  sill.  Stringers  should  be  placed  over  the  bent 
legs,  and  under  the  flume  posts,  as  the  weight  will 
then  be  transmitted  properly  to  the  ground. 

The  sills  and  posts  are  of  4  X  5 -inch  timbers. 

The  posts  are  of  4  X  5 -inch  timbers,  and  the  sills 
of  4  X  6-inch  timbers  because  of  the  notches  cut. 
The  caps  are  of  3  X  4-inch  scantling,  and  the  braces 
are  2  X  3-inch  planks. 

Flumes  are  often  placed  on  trestles  to  cross  narrow 
gulches,  some  of  which  are  from  25  to  50  feet  high. 
Fig.  57  shows  the  method  of  constructing  such  flume- 
bents  where  the  height  does  not  exceed  20  feet.  The 
dimensions  of  the  flume  for  such  situations  are  about  as 
stated,  as  there  is  no  necessity  of  increasing  their  depth 
or  width  if  the  proper  grade  is  continued  over  the 
trestle.  The  trestle  timbers  in  all  cases  should  be  cal- 
culated for  the  load  they  are  to  carry,  and  an  engineer 
employed  for  their  design  and  construction.  In  most 


CARE  OF    FLUMES 


171 


11 


11 


FIG.  57. 


ditch  lines  there  is  too  much  money  involved  to  make 
any  part  weak,  and  as  one  part  is  dependent  upon  the 
other,  should  a  break-down  occur,  the  entire  system  is 

stopped.     It  is  customary  to  i | 

arrange  overflows  at  stated 
intervals  along  the  ditch  lines, 
to  let  any  surplus  water  aris- 
ing from  rains,  snows,  or 
freshets  escape.  These  are 
placed  about  three-quarters 
of  a  mile  apart,  and  at  feeder 
stations  or  auxiliary  stor- 
age reservoirs.  When  ditches 
have  become  clogged  with 
snow  after  a  shut-down  they  must  be  cleaned  out 
before  the  water  is  turned  in,  otherwise  time  will  be 
consumed,  much  trouble  encountered,  and  possibly 
damage.  Water  will  not  melt  snow  fast,  and  will  not 
flow  through  it  at  all,  for  which  reason  sections  of  the 
ditch  must  be  shoveled  out  or  washed  out.  In  the 
latter  case  a  breach  is  made  in  the  ditch  and  the  water 
will  then  float  the  snow  through  it  rapidly.  When 
cleared  of  snow  the  ditch  is  repaired,  and  a  similar 
breach  made  lower  down  the  line,  and  so  on  to  the 
flume.  Long  flumes  must  be  shoveled  out,  or  at 
least  a  channel  made  through  the  snow  in  them. 

A.  D.  Gilchrist,  in  a  paper  presented  to  the  Australian 
Institute  of  Mining  Engineers  in  1913,  describes  a  color 
method  used  to  measure  the  discharge  of  water  from  a 
pipe  line.  For  the  purpose  one-half  ounce  of  methyl 
violet  is  dissolved  in  a  pint  of  water  and  injected  quickly 


172  WATER   SUPPLY 

into  the  stream  to  be  measured  at  the  upper  end  of  the 
pipe  line.  The  pipe  must  be  of  known  length  and  the 
time  it  takes  for  the  coloring  matter  to  pass  through  to 
the  discharge  end  gives  the  velocity  of  the  flow. 

This  apparently  crude  method  was  experimented  with 
by  Mr.  Gilchrist's  students  and  the  results  compared 
very  closely  with  weir  measurements  of  the  same  flow  of 
water  after  it  had  left  the  pipe.  The  pipe  experimented 
with  was  24-inch  diameter,  laid  on  a  grade  of  0.63  inch 
in  66  feet,  and  had  a  length  of  25,435  feet.  The  time 
which  elapsed  from  the  introduction  of  the  color  to  the 
first  vivid  show  at  the  outlet  of  the  pipe  was  2  hours  40 
minutes,  thus  giving  the  water  a  velocity  of  2.65  feet  per 
second  and  a  discharge  of  8.33  cubic  feet  per  second. 
The  weir  measurements  for  comparison  were  calculated 
by  Francis'  equation,  which  is  more  complex  than  the 
one  advanced  in  the  text  since  it  has  the  following 
expression:  /  ^ 

6  =  3.33(^-3  v».  , 

The  flow  obtained  was  8.33  cubic  feet  per  second.     . 

Hamilton  Smith's  deductions  reduced  to  the  formula 
Q  =  5.35  CB  VH3,  in  which  C  =  .603,  gave  8.35  cubic 
feet  per  second. 

The  comparison  then  between  the  color  test  and  weir 
measurements  is  sufficiently  close  to  warrant  the  use  of 
the  former,  besides  it  is  the  easier  way  of  testing  the  flow. 
Mr.  Gilchrist  states  that  the  only  reference  to  this 
method  that  he  has  been  able  to  find  was  by  Clemens 
Herschel  in  "  Experiments  on  Conduits."  He  also  draws 
the  deduction  that  whether  the  distribution  of  velocity 


CARE  OF  FLUMES  173 

over  any  cross-section  of  pipe  is  parabolic,  or  whether 
the  velocity  in  the  center  is  double  that  near  the  sides, 
there  is  no  doubt  that  the  water  in  the  pipe  moves 
forward  as  one  mass,  for  there  were  about  three  minutes 
difference  from  the  time  of  the  arrival  of  the  fastest  color 
and  the  slowest,  and  this  difference  was  largely  due  to 
method  used  in  injecting  the  color. 


CHAPTER  VI. 

PIPE    LINES   AND    DITCHES. 

IN  1852  Edward  E.  Mattison,  from  Connecticut,  with 
a  view  of  economizing  labor,  in  California  placer  mining 
conveyed  water  to  his  claim  in  a  rawhide  hose  to  which 
was  attached  a  wooden  nozzle,  for  spurting  the  stream 
against  the  gravel  bank.  This  was  the  first  step  in 
modern  hydraulic  mining,  and  was  so  appreciated  that 
canvas  hose  bound  with  wire  and  rope  soon  followed, 
and  the  nozzle  was  changed  from  wood  to  metal. 

The  canvas  hose  was  soon  superseded  by  the  inven- 
tion of  R.  R.  Craig,  who  used  at  American  Hill,  Nevada 
County,  California,  about  100  feet  of  stovepipe.  A 
firm  in  San  Francisco,  according  to  A.  J.  Bowie,  com- 
menced the  manufacture  of  wrought-iron  pipe  for 
hydraulic  mining  in  1856.  The  great  difficulty  experi- 
enced with  such  pipes  was  the  quickness  with  which 
they  rusted.  They  were,  therefore,  painted  on  the  out- 
side, but  this  did  not  prevent  their  rusting  on  the  inside. 

As  pressure  became  an  item  of  importance,  the 
strength  of  the  pipe  was  also  a  consideration,  and  as 
iron  pipe  was  costly  and  difficult  to  transport,  attention 
was  given  to  wrought  and  sheet-steel  pipe  made  in  lengths 
suitable  for  transporting  on  mules  or  burros.  Spiral- 
riveted,  galvanized  iron  pipe  was  first  introduced,  but 
this  gave  way  to  riveted  sheet-iron  and  sheet-steel  pipe, 
that  is  made  in  sizes  from  4  to  60  inches  in  diameter, 

174 


SHEET  METAL  PIPES  il75 

and  is  capable  of  resisting  pressures  up  to  600  Ibs  per 
square  inch.  The  general  impression  prevails  that  such 
pipe  is  not  suitable  either  for  pressure  or  permanency, 
yet  the  Connecticut  Tube  Works  have  been  making  for 
municipal  service  a  sheet-iron  pipe  lined  with  cement 
for  some  years,  which  they  claim  is  more  serviceable 
than  cast  iron  and  fully  as  strong  after  fifteen  years' 
service. 

Properly  constructed  sheet-metal  pipe,  when  painted 
with  asphalt  inside  and  out,  to  prevent  corrosion,  has 
lasted  twenty- five  years  and  come  into  general  use  for 
hydraulic  mining.  The  numerous  changed  conditions 
to  which  this  kind  of  pipe  has  been  subjected  have  fur- 
nished reliable  data  in  regard  to  pressure,  diameter, 
and  thickness  of  metal  required  for  various  pressures. 

The  result  of  this  experience,  briefly  stated,  is,  that  a 
comparatively  light  sheet-metal  pipe,  in  sizes  properly 
proportioned  to  diameter  and  pressure,  is  both  cheaper 
and  more  satisfactory  than  any  other  pipe  for  hydraulic 
mining. 

Asphalt  paint,  so  long  as  it  is  kept  intact,  makes  the 
pipe  practically  indestructible  so  far  as  ordinary  wear 
is  concerned.  Where  the  coating  is  worn  off  by  abra- 
sion in  transportation,  or  where  the  pipe  is  subject  to 
severe  shock  by  the  pressure  of  air  1  on  suddenly  closing 
the  gates,  or  where  expansion  and  contraction  open  the 
joints  and  break  the  asphalt,  corrosion  would  natu- 
rally occur,  but  this  can  be  remedied  by  care  and  an 
application  of  paint  to  such  places. 

In  laying  pipe   the  shortest   practicable  distance  is 

1  Water  hammering. 


1 76  PIPE  LINES  AND  DITCHES 

advisable,  wherever  the  ground  will  permit  it,  and  sheet 
pipe  should  always  have  a  solid  foundation  along  its 
entire  length.  If  it  must  cross  a  small  ravine  it  should 
be  on  a  trestle  with  its  entire  length  resting  on  plank. 
Short  turns  or  acute  angles  should  be  avoided,  as  they 
lessen  the  pressure  and  strain  the  pipe;  also,  the  pipe 
will  be  more  affected  by  expansion  and  contraction  at 
such  points. 

Wherever  practicable,  the  pipe  should  be  laid  in  a 
trench  and  covered  with  earth,  to  protect  it  as  much  as 
possible  from  contraction  and  expansion  or  injury. 
When,  laid  over  a  rocky  surface,  straw  or  rubbish  will 
protect  it  from  the  sun,  and  generally  prevent  freezing, 
especially,  if  the  water  is  in  motion.  As  a  rule,  pipe  is 
not  often  used  along  the  ditch  line,  but  runs  from  the 
reservoir  at  the  end  of  the  flume  termed  pressure  box 
down  a  steep  incline  to  the  mine. 

Pipe  laying  should  commence  at  the  lower  or  discharge 
end  and  proceed  up  the  hill.  In  the  long-distance  trans- 
mission power  plant  at  Fresno,  California1  the  construc- 
tion of  the  pipe  line  commenced  at  both  ends,  and  con- 
siderable difficulty  was  encountered  in  closing  the  gap 
at  the  center  of  the  line.  This  was  due  to  the  alteration 
in  length  resulting  from  the  change  of  temperature. 
Before  sunrise  the  opening  would  be  7  feet  8  inches,  but 
in  the  afternoon  the  gap  would  be  7  feet.  The  connec- 
tion was  finally  made  before  sunrise,  and  the  pipe  filled 
with  water  before  the  sun  had  a  chance  to  expand  it. 

There  are  two  methods  of  joining  pipe  lengths,  as 
shown  in  Fig.  58.  With  the  slip  joint  the  pipes  are  not 

1  Scientific  American,  March  27,  1897. 


Fresno  Power  Plant. 


177 


i78 


PIPE  LINES  AND  DITCHES 


of  large  diameter  or  under  very  high  head,  and  when- 
ever this  stovepipe  joint  is  used,  the  lower  end  of  each 
length  of  pipe  is  wrapped  with  cotton  drilling  or  burlap, 
to  prevent  leaking,  inserted  into  the  next  lower  length, 
and  driven  in.  Where  slip-joint  pipe  is  to  be  used  an 
allowance  of  three  inches  must  be  made  on  each  length 
of  pipe  ordered,  for  loss  in  driving  the  joints  together. 
In  case  they  leak  but  slightly,  the  leak  may  be  stopped 
by  throwing  bran  or  sawdust  into  the  pipe;  or  if  that 
does  not  answer,  dry  wooden  wedges  are  to  be  driven 
into  the  joints.  Should  the  leak  be  large,  clamps  must 
be  used  which  encircle  the  joint. 


SECTION  THROUGH  LEAD  JOINT 

b 


SHOWING  METHOD  OF  ANCHORING  PIPE.ON.A  STEEP  GRADE 
WITH  EXAMPLES  OF  LEAD  AND  SLIP  JOINTS 


FIG.  59. 


FIG.  58. 


In  laying  pipes  where  the  lengths  come  together  at 
an  angle  a  lead  joint,  Fig.  59,  should  be  used,  or  where 
the  pressure  is  great  or  the  diameter  of  the  pipe  is  large 
lead  joints  should  be  made.  This  joint  is  made  by 
means  of  a  sleeve,  a,  which  has  a  diameter  f  inch  larger 
than  the  pipe  and  into  the  space,  b,  hot  lead  is  poured. 


FLOW  OF  WATER  THROUGH  PIPES  179 

With  heavy  pressure  on  steep  grades,  the  pipe  sec- 
tions should  be  wired  together,  and  lugs  should  be  fur- 
nished on  the  outside  of  the  pipe  for  this  purpose.  Anchor 
wires  should  also  be  attached  to  the  pipe  and  to  a  stable 
object  at  intervals  on  heavy  grades.  It  is  customary  to 
make  the  pipe  of  large  diameter  and  of  light  weight 
metal  near  the  pressure  box,  and  to  decrease  the  diam- 
eter and  to  use  heavier  metal  toward  the  discharge, 

At  the  Fresno  power  plant  the  pipe  line  was  4200  feet 
long,  with  a  head  of  1411  feet,  giving  a  pressure  of  609 
pounds  per  square  inch.  This  was  built  in  three  sec- 
tions, as  follows : 

ist  Section.  — 1820  feet,  24-inch  riveted  pipe,  first 
half  No.  12  steel,  and  the  second  half  J-inch  steel  plate. 

2d  Section.  — 400  feet,  20-incJi  diameter,  lock- jointed 
welded  pipe. 

3d  Section.  —  1800  feet,  2o-inch  diameter  lap- welded 
f-inch  thick  pipe,  with  flange  joints  and  rubber  packing. 

This  column  of  water  weighs  about  317  tons,  and 
has  a  thrust  of  93  tons,  when  issuing  from  a  i^-inch 
nozzle  at  a  speed  of  9000  feet  per  minute. 

Air  escaping  from  the  Fresno  pipe  nozzle  makes  a 
noise  which  can  be  heard  several  miles.  The  noise  is 
due  to  the  expansion  of  air  as  it  leaves  the  nozzle  in 
bubbles  that  have  been  subjected ,  to  the  heavy  pres- 
sure. ^L 

The  Flow  of  Water  Through  Pipes.  —  Head  of  Water. 
—  By  head  of  water  is  meant  the  difference  in  elevation 
between  the  inlet  and  outlet  of  a  pipe,  plus  the  height 
of  the  water  above  the  center  of  the  pipe  inlet.  Water) 
pressure  is  due  to  the  head,  and  is  derived  from  the 


i8o  PIPE  LINES  AND  DITCHES 

weight  of  the  water,  hence  the  higher  the  head,  the 
greater  will  be  the  pressure.  The  pressure  due  to  a 
column  of  water  i  inch  square  and  12  inches  long  is  at 
ordinary  temperature  about  .434  pound.  For  approxi- 
mate calculations  the  pressure  may  be  considered  .5 
pound  per  square  inch  for  each  foot  in  height. 

Loss  of  Head.  —  Friction  in  pipes  may  diminish  the 
pressure  due  to  the  head  and  hence  the  power  in  three 
ways. 

i.  Resistance  to  the  flow  of  water  is  greater  in  small 
than  in  large  pipes.  The  resistance  does  not  arise 
directly  from  the  rubbing  surface,  but  is  due  to  a  layer 
of  water  that  adheres  to  the  pipe  and  acts  as  a  drag  on 
the  current.  The  amount  of  drag  is  greater  in  rough 
than  in  smooth  pipes,  and  in  short  bends  than  in  long 
bends. 

The  circumference  or  frictional  rubbing  surface  or 
perimeter  of  a  i-inch  pipe  is  3.1416  inches,  while  the 
perimeter  of  a  2-inch  pipe  is  6.2832  or  twice  that  of  a 
i-inch  pipe.  The  area  of  a  i-inch  pipe  is  .7854  square 
inch,  while  the  area  of  a  2-inch  pipe  is  3.1416  square 
inches  or  4  times  as  great.  From  this  it  is  deduced 
that  by  increasing  the  area  of  a  pipe  the  frictional  resist- 
ance is  decreased,  for  in  the  2-inch  pipe  with  twice  the 
rubbing  surface  of  the  i-inch  pipe,  4  times  the  water 
will  pass  the  head  being  the  same.  The  loss  of  head 
due  to  friction  in  pipes  is  difficult  to  calculate,  in  fact 
it  is  not:  necessary  to  make  such  calculations,  as  they 
have  already  been  made  and  tabulated  for  the  use  of 
engineers.  (See  table  on  p.  409.)  The  formula  given 


LOSS  OF  HEAD  181 

for  friction  of  water  in  pipes  is  the  simplification  of 
Weisbach's  formula  by  Coxe: 


p  _  X  5  v  -  2  ^ 

looo  d 

F  represents  the  friction  head  or  total  loss  by  friction 
in  feet;  /  the  length  of  the  pipe  line  in  feet;  d  the  diam- 
eter of  the  pipe  in  feet;  v  the  velocity  of  the  water  in  feet 
per  second. 

2.  The  flow  of  water  through  pipes  depends  upon 
the  diameter  and   length  of  the  pipe,  and   the  velocity 
due  to  the  head  principally,  but  in  addition  there  is  a 
loss  of  head  due  to  power  absorbed  in  giving  the  water 
a  uniform  rate  of  flow  or  as  it  is  termed  selling  it  in  train. 

3.  Another  amount  of  power  is  consumed  in  over- 
coming the  resistance  due   to  the  water  entering  the 
pipe. 

A  series  of  88  experiments  made  by  Hamilton  Smith, 
Jr.,  on  the  flow  of  water  through  circular  pipes  of 
various  diameters  from  J  inch  to  4  feet  are  reduced  to 
the  formula: 


v  =>m  I  — 

where 

v  =  velocity  in  feet  per  second, 

d  =  diameter  of  pipe 

I  =  length, 
A'  =  effective  head, 
m  =  variable  coefficients. 

The  effective  head   h'  was  derived   from  the  total 


182  PIPE  LINES  AND  DITCHES 

liead  h  as  follows,  c  being  the  coefficient  of  contraction 
at  entrance  : 


in  which 

g  =  acceleration  of  gravity. 

Strength  of  Pipes.  —  Pipe  lines  generally  involve 
considerable  outlay,  and  must  be  proportioned  for 
strength  as  well  as  capacity.  The  bursting  and  safe 
strength  of  iron  and  steel  pipes,  and  their  construction 
should  be  understood,  although  the  table  on  pp.  336-338 
gives  the  safe  working  pressure  for  double-riveted  pipe 
up  to  42  inches  in  diameter. 

To  calculate  the  safe  working  pressure  for  iron  or 
steel-plate  pipes,  the  following  formula  advanced  by 
Professor  Rankin  may  be  used.  In  the  formula  P  is 
the  safe  working  pressure  in  pounds  per  Square  inch; 
T  is  the  tensile  strength  of  the  plate,  iron  being  taken 
at  48,000  and  steel  62,000  pounds  per  square  inch;  t  is 
the  thickness  of  the  plates  in  decimals  of  an  inch;  c  the: 
factor  of  safety  usually  assumed  as  4;  /  is  the  propor- 
tional strength  of  plates  after  riveting,  the  factor  being 
.7  for  double-riveting  and  .5  for  single  riveting;  R  is  the 
radius  of  the  pipe  in  inches.  - 


Example.  —  Having  a  head  of  75  pounds  per  square 
inch,  of  what  thickness  should  a  double-riveted  36-inch 
diameter  iron  pipe  be>  with  4  used  as  a  factor  of  safety? 


STRENGTH  OF  PIPES  183 

Solution.  —  Factoring  the    equation    for    /,    the    for- 


mula  becomes  /  =  -r—  -  and  by  substituting  the  values 
given 

4  X  75  X  4f 
t       L2  -  a 


A        r      /48,ooo  X  i6\ 

p        )  *  f  =  (    x6  )  *  -7  ==  75  pounds 


48,000  X  .7 

Example.  —  What  will  be  the  safe  working  pressure 
for  a  pipe  36  inches  in  diameter,  made  of  .1  6-inch  sheet 
iron  and  double-riveted,  where  using  a  safety  factor 
of  4? 

T 

4x36 

pressure.     Ans. 

When  sheet-iron  pipe  is  left  to  the  option  of  the  maker 
the  lengths  are  generally  27  feet.  When  Sit  is  to  be  trans- 
ported by  wagon  the  lengths  are  20  feet.  When  the  pipe 
is  for  heavy  pressure  and  mule  packing  it  is  made  in 
sections  of  24  to  30  inches  in  length,  rolled  lengthwise 
and  punched,  with  rivets  furnished  to  put  the  pipe 
together  on  the  ground'  where  laid.  Sheet  metal  for  this 
purpose  can  be  riveted  cold,  with  the  ordinary  riveting 
and  flanging  tools.  Sheet  iron  or  steel  in  this  form  has 
a  discount  of  30-  per  cent  from  completed  pipe.  After 
riveting,  the  pipe  should  be  tarred  or  painted  with  asphalt 
and  allowed  to  dry. 

Pipe  should  be  dipped  in  asphaltum  heated  to  a  tem- 
perature of  300°  F.  and  allowed  to  remain  in  the  bath 
until  the  metal  attains  the  same  temperature.  The 
material  for  pipe  construction  should  have  No.  8,  10,  12, 
14,  1  6,  and  18  B.  G.,  thicknesses,  according  to  pressure, 


184 


PIPE  LINES  AND  DITCHES 


and  iron  plate  will  usually  prove  more  satisfactory  than 
steel  plate,  as  the  latter  oxidizes  and  flakes  readily. 

Pipe  Elbows.  —  The  additional  head  required  for 
bends  is  given  on  pages  314  and  318.  No  bends  should 
be  allowed  in  a  pipe  line,  where  the  pipe  is  long  or  the 
pressure  heavy,  that  have  a  radius  less  than  five  diame- 
ters of  the  pipe.  The  simplest  rule  for  calculating  the 
loss  of  head  due  to  bends  of  various  angles  in  a  pipe  is 

H  =  .0152  V2K. 

in  which  K  is  a  coefficient  to  be  taken  from  the  following 
table: 


Angle  of  Bend 

20° 

40° 

60° 

80° 

90° 

100° 

120° 

K               ... 

046 

139 

364 

74 

98 

1  26 

1  86 

When  the  radius  of  the  bend  is  greater  than  five  diam- 
eters of  the  pipe  the  loss  may  be  calculated  by  multi- 
plying the  number  of  degrees  in  the  angle  by  the  square 
of  the  velocity  in  feet  per  second,  and  dividing  the  product 
by  88,489. 

Example.  —  With  a  bend  having  an  angle  of  100°  and 
discharging  water  at  a  velocity  of  20  feet  per  second, 
the  loss  of  head,  will  be 


202    X    100° 

88,489 


=  .45  feet. 


When  the  radius  is  less  than  five  times  the  diameter, 
fairly  accurate  results  may  be  obtained,  by  multiplying 
the  square  of  the  velocity  of  the  water  in  feet  per  second, 


WATER  GATES 


by  C,  a  coefficient  having  the  following  angles: 


10°  C.  =  .000109 
20°  C.  =  .000466 


50°  C.  =  .003634 


30°  C.  =  .001134 
40°  C.  =  .002158 


60°  C.  =  .005652 
70°  C.  =  .008276 
80°  C.  =  .011591 
90°  C.  =  .015248 

There  has  not  been  sufficient  investigation  on  this 
subject  to  enable  the  engineer  to  make  exact  allowance 


FIG.  60. 

for  friction  due  to  bends,  and  all  calculations  are  there- 
fore approximate. 

Water  Gates.  —  Pipe  lines  would  be  incomplete  with- 
out water  gates.  A  section  and  cross  section  of  a  gate 
valve  is  shown  in  Fig.  60.  The  gate,  a,  slides  vertically 
up  and  down,  so  that  when  fully  open  there  is  practically 
no  interference  with  the  flow  through  the  pipe.  The 


i86 


PIPE  LINES  AND  DITCHES 


valve  gate  casing,  b,  is  cast  iron,  reinforced  by  a  web  in 
its  circular  part  and  with  a  stem,  c,  terminating  in  a  screw. 
By  means  of  the  movable  nut  provided  with  levers  in  the 
top  of  a  yoke,  d,  the  screw  is  made  to  turn  and  move 


FIG.  6 1. 


the  gate  upwards  or  downwards.  The  lower  end  of  the 
stem  is  fitted  in  a  box  collar,  e,  in  order  that  it  may  turn 
freely.  Whenever  a  junction  is  made  with  another  pipe 


AIR  VALVES 


187 


line  the  custom  is  to  fork  the  lines  rather  than  use  elbows. 
Two  such  gate  valves  are  then  used,  one  in  each  branch 
pipe,  as  shown  in  Fig.  61.  All  gate  valves  should  have 
outside  yokes  and  coarse  screw  threads  to  prevent  quick 
closing  and  the  consequent  water  hammer. 

Air  Valves.  —  There  should  be  two  working  faces  in 
any  hydraulic  mine,  so  that  one  may  be  worked  while  the 
pipe  is  being  advanced  in  the  other.  This  is  accom- 
plished by  running  the  main  pipe  line  into  the  center  of 
the  mine  and  using  a  Y  which  has  water  gates  on  each 
branch  line.  The  stand  pipe  shown  in  Fig.  61  is  an  air 
chamber,  supplied  with  a  pop  valve  at  the  top  that 
allows  the  air  to  escape  after  it  reaches  a  certain  pressure. 
Its  object  is  to  prevent  water  hammer,  and  possibly 
damage  to  the  pipe  line,  also  to  collect  air  before  it  leaves 
the  pipe  nozzle.  To  allow  the  escape  of  the  air  from  a 


FIG.  62. 


pipe  line  while  filling,  and  also  to  prevent  the  formation 
of  a  vacuum  and  collapse  of  the  pipe  in  case  of  a  break 


i88 


PIPE  LINES  AND  DITCHES 


in  the  pipe  line,  air  valves  are  required.  The  valve 
shown  in  Fig.  62  is  automatic  in  its  action,  and  quite 
simple  in  comparison  with  some.  When  the  water  fills 
the  pipe  it  raises  the  valve,  a,  and  when  it  leaves  the  pipe 
the  valve,  a,  immediately  drops  and  allows  air  to  enter, 
thus  preventing  a  collapse.  Air  valves  of  this  descrip- 
tion or  some  other  should  be  placed  wherever  there  is  a 
knuckle  or  high  place  in  the  pipe  line  and  where  air  is 
likely  to  accumulate  or  a  vacuum  occur.  At  all  low 
places  similar  blow-off  valves  should  be  placed. 

The  Pressure  Box.  —  In  order  to  prevent  sand,  gravel, 
sticks,  and  rubbish  from  going  into  the  pipe  line,  and 


FIG.  63. 

particularly  to  prevent  the  admission  of  air,  a  pressure 
box  is  used.  The  pressure  box,  Fig.  63,  should  be 
large,  and  the  water  should  stand  at  least  4  feet  over 
the  entrance  to  the  pipe  in  order  to  prevent  the  admis- 
sion of  air.  The  pipe  should  be  funnel-shaped  where 
the  water  enters  it,  if  it  can  be  placed  horizontal,  but  if 
it  can  not  be  so  placed  the  pipe  should  be  as  in  the  cut, 
and  firmly  anchored. 

There  should  be  a  gate,  G,  at  the  reservoir  or  flume 


THE  PRESSURE  BOX  189 

at  the  head  of  the  pipe  line  to  cut  the  water  off.  There 
should  also  be  pressure  indicators  and  water  regulators 
which  will  regulate  the  flow.  The  cheapest  gate  at  the 
head  of  the  pipe  line  or  along  the  ditches  and  flumes 
where  pressure  is  not  excessive  is  constructed  of  plank 
about  as  long  as  the  water  course  is  wide,  and  8 
inches  high.  These  are  placed  one  above  the  other, 
in  grooves,  so  they  may  easily  be  removed  and  replaced. 
The  grooves  are  formed  by  nailing  2  X  3-inch  plank  to 
the  side  of  the  flume,  and  through  these  guides  the  gate 
planks  are  lowered  and  raised  from  the  top.  Consider- 
able trash  is  at  all  times  moving  with  the  water  in  the 
ditches,  hence  for  floating  rubbish  the  flume  and  pressure 
box  should  have  inclined  bars  of  wood  or  iron  to  prevent 
it  reaching  the  pipe.  Sand  is  collected  by  placing  iron 
bars,  S',  across  the  bottom  of  the  flume  over  a  box, 
SB,  let  into  the  bottom  as  shown. 

To  prevent  sand  and  gravel  from  entering  the  pressure 
box,  there  should  be  an  increased  depth  and  width  to 
the  ditch  for  at  least  100  feet  back  from  the  pressure 
box.  There  should  also  be  a  small  gate,  G',  in  the 
sand  box  for  blowing  out,  and  the  pipe,  P,  should  be 
from  2j  to  4  inches  above  the  floor  of  the  pressure  box. 

The  gate,  G,  regulates  the  flow  of  water  into  pipe,  P, 
and  shuts  it  off  entirely  if  a  small  waste  gate  is  placed 
on  the  flume  side.  The  same  construction  for  gates  may 
be  used  in  dams,  flumes,  and  ditches.  Water  gates  are 
expensive  when  made  of  metal,  but  in  some  instances 
they  will  be  required  in  the  pipe,  near  the  pressure  box. 

Under  heavy  pressure  they  are  not  easy  to  work,  and 
wear  out  fast. 


igo  PIPE  LINES  AND  DITCHES 

Filling  Pipes.  —  Care  must  be  taken  when  filling 
pipes  to  introduce  the  water  gradually,  in  order  to  pre- 
vent serious  accidents.  For  this  reason  it  is  probably 
a  good  plan  to  place  a  gate  valve  in  the  pipe  below  the 
pressure  box,  in  order  to  regulate  the  intake  flow.  Air 
will  enter  a  pipe  in  surprising  quantities,  and  in  one 
instance  enough  air  was  taken  in  at  a  power  plant  to 
run  an  engine  or  a  rock  drill.  The  water  before  it 
enters  the  pipe  should  be  free  from  air  and  should  enter 
quietly,  this  as  mentioned  can  be  accomplished  to  some 
extent  by  placing  the  pipe  some  distance  under  water, 
say  4  feet.  Before  filling  the  pipe  all  stones  and  rub- 
bish are  to  be  removed. 

Ditch  Lines.  —  Surveys  are  necessary  to  the  design 
and  construction  of  a  ditch,  as  the  course  of  the  ditch  is 
confined  to  narrow  limits  by  the  topography  of  the 
country  through  which  it  passes. 

The  survey  will  begin  at  some  point  very  near  the 
storage  reservoir  site,  and  will  generally  follow  the  same 
valley  as  the  stream  that  was  impounded  for  a  consider- 
able distance.  It  will  be  found  that  careful  surveys  in 
such  operations  pay  because  more  accurate  work  can 
be  done  in  their  construction.  As  far  as  alignment  is 
concerned,  this  survey  does  not  call  for  any  great  degree 
of  accuracy,  the  leveling  being  of  much  more  impor- 
tance. Errors  are  liable  to  occur  in  leveling.  There, 
fore,  when  the  alignment  has  been  completed  and  leveled, 
check  levels  should  be  run  back  over  the  entire  line.  It 
will  not  be  necessary,  to  verify  the  entire  profile,  a  check 
on  the  benches  being  sufficient.  All  important  tribu- 
taries should  also  be  surveyed,  carrying  the  survey  to  an 


DITCH  LINES  191 

elevation  approximately  equal  to  that  of  the  reservoir 
site.  The  approximate  length,  together  with  the  total 
fall  obtained  from  this  survey,  will  enable  the  engineer 
to  make  a  preliminary  design  of  the  section  and  grade 
for  the  ditch. 

A  trial  line  for  the  ditch  can  now  be  run.  For  this 
purpose,  suppose  a  grade  of  13.2  feet  to  the  mile  is 
decided  on  for  the  slope  of  the  ditch.  The  tangent  of 

I  3  2 

the  angle  corresponding  to  this  slope  is  -^—  =  .0025, 

5280 

which  corresponds  to  an  angle  of  nearly  9  minutes. 
Having  a  transit  provided  with  a  vertical  limb,  let  the 
telescope  be  depressed  to  this  angle  and  clamped.  When 
the  transit  is  set  up,  let  the  target  of  a  leveling  rod  be 
set  at  the  height  of  the  telescope  of  the  transit  from  the 
ground.  This  can  •  be  sufficiently  approximated  by 
holding  the  rod  alongside  of  the  transit  and  sighting 
across  the  wyes.  Let  the  rod  now  be  taken  as  far  ahead 
as  possible  and  moved  along  the  ground,  up  or  down 
hill,  until  the  center  of  the  target  is  bisected  by  the 
horizontal  cross-hair  of  the  transit.  The  foot  of  the 
rod  is  on  the  ground  falling  at  the  desired  rate,  and  a 
plug  should  be  driven  at  this  point  and  the  distance 
measured.  The  direction  will  be  ascertained  by  the 
needle,  as  this  will  be  sufficiently  accurate.  From  time 
to  time  measurements  will  be  taken  to  convenient  sta- 
tions on  the  line  of  the  survey,  if  one  has  been  made,  as 
a  check.  It  will  be  well  to  carry  this  line  along,  follow- 
ing all  the  indentations  and  tributary  valleys,  for  in  this 
way  the  length  of  a  line  following  the  natural  surface 
of  the  ground  for  its  entire  distance  will  be  obtained. 


ex 
£ 


192 


DITCH  LINES  193 

It  will  be  very  rare  that  this  line  is  actually  followed  by 
the  ditch.  Valleys  will  be  crossed  by  trestles  or  siphons 
and  hills  will  be  tunneled,  but  only  in  this  way  can  an 
estimate  of  the  comparative  advantages  of  alternative 
ditch  lines  be  compared. 

When  an  approximate  location  of  the  ditch  has  thus 
been  determined,  the  line  will  be  accurately  re-run  and 
leveled  over,  so  as  to  establish  the  final  location  and 
make  a  more  nearly  exact  estimate  of  cost. 

The  material  in  which  the  ditch  is  excavated  will 
place  restrictions  on  the  velocity  of  the  water.  The 
velocity  should  be  sufficient  to  prevent  the  deposition  of 
silt  and  not  so  great  as  to  erode  the  bottom  and  sides  of 
the  ditch.  The  grade  necessary  to  maintain  a  uniform 
velocity  within  the  desired  limits  will  depend  on  the 
interior  surface  of  the  ditch,  being  very  much  less  for 
one  having  a  smooth  lining  than  for  one  having  a  rough 
lining.  The  area  of  cross  section  also  is  a  function,  for 
the  water  in  a  large  and  deep  ditch  will  move  with  a 
greater  velocity  under  a  given  grade  than  that  in  a 
smaller  and  shallower  one  having  the  same  grade.  The 
form  of  the  cross  section  also  exerts  an  influence  on  the 
velocity  of  flow,  so  that  the  determination  of  the  grade 
becomes  a  complex  problem,  depending  on  the  desired 
discharge  of  the  ditch,  its  rubbing  surface  and  form, 
and  the  dimensions  of  its  cross  section 

Gravity  is  the  sole  force  that  acts  on  water  in  a 
ditch  to  produce  the  motion  which  takes  place.  The 
inclination  of  the  surface  of  the  water  in  the  ditch 
is  the  immediate  cause  of  motion,  being  that  'which 
enables  gravity  to  act. 


1 94  PIPE  LINES  AND  DITCHES 

It  is  evident  that  the  steeper  the  ditch  grade  the 
greater  will  be  the  velocity  of  the  water;  and  as  this 
grade  is  determined  by  the  ratio  of  the  vertical  height 
to  the  distance  in  which  it  is  overcome,  it  is  evident 
that  the  accelerating  force  producing  velocity  will  be 

expressed  by  the  ratio  -j  ,  in  which  h  =  the  difference  of 

level  between  the  two  extremities  of  the  ditch  and  /  == 
the  distance,  usually  measured  horizontally,  separating 
the  two. 

If  there  were  no  resistance  to  the  flow  of  water  through 
the  ditch,  the  constant  accelerating  force  would  cause 
the  velocity  to  go  on  increasing  indefinitely.  Owing, 
however,  to  resistances  the  water  soon  acquires  a  con- 
stant velocity,  provided  the  ratio  —  remains  constant. 

If 

There  are  resistances  that  increase  in  intensity  with  the 
increase  of  velocity,  so  that  after  a  certain  time  the 
increasing  resistance  just  equals  the  increasing  accelera- 
tion, and  the  velocity  then  becomes  constant  or  assumes 
a  permanent  regimen. 

The  laws  bearing  on  the  subject  of  the  flow  of  water 
in  ditches,  may  be  expressed  as  follows: 

I.  The  resistance  for  any  given  velocity  is  propor- 
tional to  the  wet  perimeter  or  the  surface  over  which  the 
water  flows. 

II.  This  resistance  affects  the  entire  volume  of  water 
being  greatest  for  the  film  in  immediate  contact  with  the 
wet  perimeter,  and  becoming  less  and  less  for  the  films 
and  threads  more  remote  from  that  surface. 

III.  The  greater  the  surface  in  contact  with  a  given 


DITCH  FORMULAE  195 

volume  of  water,  the  greater  the  resistance  becomes;  con- 
versely, the  greater  the  volume  subject  to  a  given  resist- 
ance, the  less  will  the  velocity  be  affected. 

IV.  The  resistance  is  nearly  proportional  to  the  square 
of  the  mean  velocity  of  flow. 

V.  The  resistance  varies  with  the  nature  of  the  ditch 
ground,  being  greater  for  a  rough  surface  and  less  for  a 
smooth  one. 

Let 

h  =  difference  in  level  between  ends  of  the  ditch  or 

any  two  cross  sections  of  the  ditch. 
I  =  horizontal  length  of  that   portion   of  the   ditch 

included  between  the  sections  whose  difference 

of  level  is  h. 

g  =  grade  =  ratio  -  • 
/ 

a  =  area  of  water  cross-section. 
p  =  wet  perimeter. 

r  =  hydraulic  mean  radius  =  ratio  —  • 

P 
cf  =  coefficient  depending  on  the  ground  in  which  the 

ditch  is  excavated. 
•     v  —  the  mean  velocity  of  flow. 

Then,  the  resistance  to  flow  may  be  expressed  by  the 
equation  ha  =  c'lpv2,  from  which  the  formula 


is  derived. 

By  replacing  the  factor  y  —  by  an  equivalent  factor,  c, 
then  v  =  cVrg. 


196  PIPE  LINES  AND  DITCHES 

Form  for  Ditches.  —  It    is  evident  from  the  formula 
that  the  velocity  increases  with  the  hydraulic  mean  radius 

r  =  — ,  and  that  therefore  the  most  favorable  shape  of 

cross  section  will  be  the  one  in  which  a  given  area  is 
enclosed  by  the  smallest  wet  perimeter.  In  the  case  of 
a  ditch,  this  section  would  be  a  half  circle,  since  the 
circle  is  that  geometrical  figure  which  encloses  the  greatest 
area  within  a  given  perimeter.  In  the  case  of  the  circle, 
the  value  of  the  hydraulic  radius  is 


and,  since  both  the  area  and  the  wet  perimeter  of  a  half 
circle  are,  respectively,  equal  to  one-half  of  the  area  and 

wet  perimeter  of  a  circle  when  running  full,  the  ratio  — 

for  the  half  circle  is  also  equal  to  —  • 

The  half-circle  form  is  an  impracticable  form  for  a 
ditch,  since  it  could  not  be  constructed  and  maintained 
unless  lined  with  masonry  or  some  other  permanent 
material,  and  even  then  the  constructional  difficulties 
would  generally  render  this  form  inadvisable,  as  entail- 
ing a  considerable  expense  for  labor  without  a  correspond- 
ing economy  of  material.  An  approximation  to  this 
best  form  is  half  a  regular  hexagon,  in  which 


D  being  the  diameter  of  the  circumscribing  circle.     This 
form  would  also  require  a  permanent  lining  if  it  were 


TRAPEZOIDAL  DITCHES  197 

applied  to  an  earthen  ditch,  and  would  not,  therefore, 
always  be  consistent  with  the  character  of  the  ground 
and  the  velocity  of  flow.  The  form  of  a  ditch,  there- 
fore, should  not  be  hexagonal,  from  the  fact  that  unless 
the  sides  are  of  hard  rock  they  will  wash  considerably. 
Ditches  having  the  trapezoidal  form  can  have  their  sides 
made  to  conform  with  the  natural  slope  of  the  material 
and  its  hardness.  Again  trapezoidal  ditches  offer  less 
rubbing  surface  for  equal  water  areas  than  rectangular 
ditches.  On  the  other  hand  the  trapezoidal  form  is  less 
adapted  to  withstand  losses  of  water  from  percolation 
and  evaporation  that  occur,  owing  to  the  large  area  of 
water  surface  exposed  to  the  air,  and  its  largest  area 
of  ground  exposed  to  the  pressure  of  water.  The  re- 


FIG.  64. 

lations  existing  between  the  various  dimensions  of  a 
trapezoid  are  best  illustrated  graphically.  The  area  of  a 
trapezoid  is  found  by  adding  together  the  length  of  the 
parallel  sides,  dividing  the  sum  by  2,  and  multiplying 
the  quotient  by  the  perpendicular  height  ec.  Thus  in 
Fig.  64 

area  = 


The  angle  of  slope  eac  is  equal  to  —  =  cot.  eac.  The  peri- 

€C 


198 


PIPE   LINES  AND  DITCHES 


meter  is  ac  +  cd  +  db.  The  side  ac  is  the  hypothenuse 
of  the  right  triangle  aec,  and  hence  ac  =  \/ae2  +  ec2. 

The  relative  slope  of  the  sides  of  a  ditch  are  expressed 
by  stating  the  ratio  of  the  base  ae  to  the  height  ec  of  the 
triangle  aec. 

Size  of  Ditches.  —  The  following  table  is  composed 
of  subject  matter  obtained  from  Molesworth's  Pocket 
Book"  and  from  C.  C.  Longridge,  "Hydraulic  Mining." 

It  will  be  found  useful  for  comparison  between  the 
different  ditch  sections,  and  for  ascertaining  the  size 
of  ditches  to  carry  a  given  quantity  of  water. 


Angle 
a 
Degrees. 

Slope 
of 
Sides. 

Vertical 
Depth. 

Width 
at 
Top. 

Width 
at 
Bottom. 

Perimeter 
p  =  Va 
X  Factor, 
Factors. 

90°  oo' 

Vertical 

•  7°7V/« 

.4i4V^ 

1.414^/0 

2.828 

78°  4i' 

.200 

•734\/a 

•5io\/a 

i.2i7Va 

2.713 

75°  58' 

.250 

•734\/a 

•533\/a 

i.i6iv/a 

2.692 

7i°  34' 

•333 

•  752\/a 

•  58oV^ 

i.o79V/a 

2.656 

63°  26' 

.500 

•7S9AA 

.697^ 

•  938\/a 

2-635 

60°  oo' 

•577 

•  76o\/a 

•755\A 

•877V« 

2.632 

56°  19' 

.667 

•759^0 

.824Vo; 

.8i2v^ 

2-635 

53°    8' 

•75° 

•757  Va 

•  892^/0 

•753\/a 

2  .  645 

51°  20' 

.800 

•753Va 

i  .  96o\/^ 

•  724\/a 

2.654 

45°  oo' 

.000 

•  74Q\/a 

2.o92»v/a 

•6i3\/a 

2.704 

40°  oo' 

.192 

•  722\/a 

2.246\/a 

•525\/a 

2.771 

36°  52' 

•333 

•7°7\A 

2-557\/a 

•  47i\/« 

2.828 

35°  oo' 

.402 

•  697x/a 

2  .  430  \/a 

•439Va 

2.870 

33°  4i' 

.500 

.689^ 

2.465\/a 

.4i8v^ 

2.989 

30°  oo' 

1.732 

•  664v^ 

s^av^ 

•356\/a 

3.012 

26°  34' 

2.OOO 

'6$<K/3 

2  .  844^7^ 

•  300Va 

3-144 

21°  48' 

2.500 

•  S&vVa 

3-i7°\/a 

.288^ 

3-397 

1  8°  26' 

3.OOO 

•  548\/a 

4-ooiv^ 

.ii9\/a 

4.121 

DITCH  CALCULATIONS  199 

Example.  —  What  are  the  best  dimensions  to  give  a 
ditch  when  the  angle  of  slope  is  45°,  the  discharge 
36  cubic  feet  per  second,  and  the  velocity  4  feet  per 
second. 

Solution.  —  From  formula 


hence,  a  =     —  =  9  square  feet  area. 

4 

Then  vertical  depth  =  .740  Va  =  .740  X  3  =  2.22  feet. 
Width  at  top  =  2.092  Va  =  2.092  X  3  =  6.276  feet. 
Width  at  bottom  =  .61  ^V  a  =  .613  X  3  =  1.839 

...            ab  —  cd      6.276  —  1.830 
Length  of  ae  = =  — ' ^  =  2.218. 

o  o 


2 


Length    of    side    ac  =  Vae2  +  ce2  =  A/2.222  +  2.222 

=  3.14  feet. 

Perimeter  =  3.14  +  1.839  +  3-J4  =  8-12  ^eet- 
Example.  —  What  will  be  the  best  dimensions  for  a 
ditch  when  the  angle  of  slope  is  60°,  the  discharge  50 
cubic  feet  per  second,  and  the  velocity  2  feet  per  second. 

Solution. —  a  =  -**  =  ^—  —  25  square  feet. 

V  2 

The  vertical  depth  =  .760  \/25  =  3.80  feet. 
Width  at  top  =  1.775  ^2S  =  8-875  feet- 
Width  at  bottom  =  .877  \/25  =  4.385  feet. 

-     r           ab—  cd      8.87S  -  4.385 
Length  of  ac  =  =  — '-^ ^  °  °  =  2.24. 


Length  of  side  ac  =  V^.So2  +  2.242  =  4.41  feet. 
Perimeter  =  4.41  +  4.41  +  4.385  =  13.21  feet 


200  PIPE  LINES  AND  DITCHES 

Flow  of  Water  in  Ditches.  —  An  approximate  formula 
that  may  be  used  for  ditches  with  earthen  banks  in  good 
condition  is  the  following: 


100,000  r2s 
9^+35 

in  which          v  =  mean  velocity  in  feet  per  second; 

r  =  hydraulic  radius  =  -  ; 

P 

s  =  the  slope  =  -  . 
i 

Example.  —  What  will  be  the  mean  velocity  of  flow 
in  trapezoidal  ditch  having  a  fall  of  5.25  feet  per  mile, 
and  the  following  dimensions:  Top  28  feet;  bottom, 
10  feet;  length  of  sides,  10.3  feet;  depth  5  feet. 

Solution.  —  Here,  s  =    5'  5  _  tOOOg^  -j.  ?  which  call 
5,280 

.001.    Also,  r  =  ^7=3.105. 

Then 

4  / 100.000  X  0.64  X  .001  .  , 

v  =  V ' =3-9i  feet  per  second. 

27-95  +  35 
Ans. 

In  the  example,  the  velocity  is  nearly  4  feet  per  second, 
would  this  be  too  great  for  the  earthen,  banks  of  a  ditch 
to  resist  without  washing?  The  answer  to  this  question 
can  only  be  given  by  referring  to  the  results  of  experience. 
It  has  been  found  that  light  and  sandy  soils  cannot 
withstand  a  mean  velocity  greater  than  2  feet  per  second, 


WATER  VELOCITY  IN  DITCHES 


2OI 


while  at  the  same  time  this  velocity  is  sufficient  to  pre- 
vent plant  growth  and  remove  silt.  In  firmer  soil, 
velocities  of  3  to  4  feet  per  second  are  permissible,  but, 
except  in  hard  pan  or  very  resisting  material,  5  feet 
seems  to  be  the  limiting  velocity  of  earthen  ditches. 

In  a  district  where  it  is  proposed  to  build  such  ditches 
there  will  be  some  examples  of  ditching,  upon  a  greater 
or  less  scale,  by  observing  which  an  approximate  idea 
may  be  formed  of  the  proper  grade  and  side  slopes  to 
be  given  to  the  proposed  ditch,  or  if  there  are  no  ditches 
the  engineer  must  be  employed. 

Side  Slope  for  Ditches.  —  The  following  table  is  given 
by  some  authorities  as  the  proper  velocity  for  the  maxi- 
mum flow  in  ditches,  and  the  proper  slope  to  give  the 
sides  of  ditches  in  different  materials. 


Material  of  Sides. 

Angle 
of  Sides 

Slope  = 
Base 

Maximum 
Velocity 

in  FVet  T*pr 

Degrees. 

Perpendicular 

Second. 

oo 

Vertical 

10'  per  sec. 

Bedded  rock  .  . 

oo 

Vertical 

6'  per  sec 

Schists  .  

oo 

Vertical 

4e'  Der  sec. 

Puddled  clay  

Af 

in   i 

4'  per  sec 

Gravel  1.5  in.  diameter.  .  . 
Gravel  i  in.  diameter  .  .  . 
Gravel,  coarse  sand.  .  .  . 
Gravel,  fine  sand  .... 
Clay  and  soil  

40 
40 
35 
3° 
20 

in.  i  .  19 
in.  1.19 
in.'  i.  42 
in.  1.73 
in  2  74. 

3  .  25'  per  sec. 
2  .  25'  per  sec. 
.  75'  per  sec. 
.   5'  per  sec. 
.25'  per  sec. 

Besides  the  velocity  and  side  slope  there  are  other 
factors  that  influence  the  choice  of  form  of  the  cross 
section  of  a  ditch,  and  a  certain  depth  will  generally  be 


202  PIPE  LINES,  AND  DITCHES 

found  more  convenient  or  desirable  than  another.  The 
following  example  will  make  this  plain. 

It  is  desired  to  establish  the  proper  cross  section  and 
grade  of  a  ditch  under  the  following  circumstances: 
The  quantity  of  water  to  be  conveyed  is  150  cubic  feet 
per  second.  A  velocity  of  2  feet  per  second  is  desired. 
The  side  slopes  are  to  have  an  inclination  of  i  vertical 
to  i  J  horizontal,  and  a  depth  of  3  feet  of  water  is  desired 
in  the  ditch.  What  should  be  the  form  and  area  of  the 
cross  section,  and  what  the  grade  of  the  ditch  ? 

Since  the  velocity  is  to  be  2  feet  per  second,  and  the 
discharge  150  cubic  feet  per  second,  from  the  formula 


a  =      =  the  area  will  be  --  =75  square  feet. 

To  determine  the  form  which  this  area  must  have 
it  is  necessary  to  know  the  bottom  width  of  the  ditch. 

Since  the  vertical  height  is  3  feet,  and  the  slope  is  to 
have  an  inclination  of  i  to  ij;  ae,  in  Fig.  38,  is  4.5  feet. 
From  this  data,  let  x  =  bottom  and  xe  X  2  a  or  9  =  top, 

then  the  area  =  ^  -  **  =  75  or  12  x  4-  54  =  150, 


2 


and    x  =  8.     ac    will    then  =  V^2  -f-  4.5*  =  5.4;    and 

p  =  5.4  +  5-4  +  8  =  18.8. 

Since 

a       7< 

r  —  —  =   /3    =  4. 
p      18.8 

All  the  necessary  data  is  now  at  command  except  s,  and  to 
obtain  this  insert  all  the  data  in  formula 

•    , /i 00,000  r2s  _     _  *  /ioo,ooo  X  16  X  s 

"  *    9'  +35  *'Y       9X4+ 35 

100,000  X  1 6  X  s  . 
4=-         —         - 


DEPTH  AND  VELOCITY  203 

hence 

284 

5  =    — * =  .00017 

I,6oo,OOO 

as  the  grade  and  this  is  equal  to  .00017  X  5280  =  .897 
feet  per  mile. 

Depth  and  Velocity  of  Flow.  —  The  depth  of  a  ditch 
exercises  considerable  influence  on  the  velocity  of  flow. 
For  instance  in  the  example,  if  the  depth  had  been  6  feet, 
other  data  remaining  the  same,  the  bottom  width  would 
be  24  x  -i-  108  =  150  and  x  =  1.75.  The  sides  would 
be  10.8  feet,  and  the  wet  perimeter  21.91  feet.  The 
hydraulic  radius  3.42,  the  square  of  which  is  11.69. 
Then 

100,000  X  11.69  X  s 

9  X  11.69  +  35 
and 

s  =  —*—  =  .00048. 
8350 

This  represents  a  grade  of  2.53  foot  to  the  mile,  where 
with  the  previous  depth  it  was  .897  foot  per  mile. 

On  comparison  these  examples  show  that  with  a  given 
grade  and  area  of  cross  section,  the  velocity  becomes 
greater  as  the  depth  increases,  because,  within  certain 
limits,  the  hydraulic  radius  increases  with  the  increase 
in  depth.  The  limit  is  reached  when  the  width  of  the 
ditch  is  equal  to  twice  its  depth.  This  condition  is  most 
perfectly  fulfilled  in  the  case  of  a  ditch  having  a  semi- 
circular cross  section. 

As  a  further  illustration  to  show  the  effect  of  depth 
on  velocity,  take  the  semi-hexagon  form,  although  it 
is  an  unpractical  form  for  earthen  ditches. 


204  LINES  AND  DITCHES 

The  semi-hexagon,  Fig.  65,  is  inscribed  in  a  semi- 
circle. Since  the  side  of  a  regular  hexagon  is  equal  to 
the  radius  of  the  circumscribing  circle,  the  relation 


2 


FIG.  65. 

between  the  various  parts  shown  in  the  figure  exists. 
The  side  x,  is  required  first,  and  the  depth,  which  is 

x  V? 

Since  the  area  in  the  first  illustrative  example  is 

"V        OC  \/  3 

--  * 


75    square  feet,  ^-  X  --  *  =  75;    V3  oc2  =  100,  and 
oc  =  18.24.     In  a  ditch  having  the  form  of  a  semi-hexa- 

gon the  hydraulic  radius  is  equal  to  —  —  —  in  which  for- 

8 

mula,  d  =  the  diameter  of  the  circumscribing  circle  or 
2  x.    In  the  example  under  discussion,  therefore, 


18.24X2  X  1.73 
8 


and 


Vioo,ooo  X  7.9  X  7.9  X  s 
9  X  7.9  +  35 


or 

s  =  0.0067  or  3-53  f°°t  per  mile  grade. 


SIPHONS  205 

Siphons.  —  There  are  occasions  when  pipes  are  placed 
in  ditch  lines  to  carry  water  across  valleys  that  can  not 
be  spanned  by  trestles. 

Pipes  used  for  this  purpose  become  inverted  siphons, 
but  have  received  the  name  of  siphons.  Water  will  seek 
its  level,  but  owing  to  the  friction  in  the  siphon  and  the 
necessity  of  having  a  head  to  create  a  flow,  the  entrance 
to  the  siphon  must  be  higher  than  its  discharge.  Near 
Discovery,  in  Atlin,  British  Columbia,  the  water  from  a 
ditch  is  carried  across  the  valley  in  a  steel  siphon,  where 
it  is  delivered  to  a  second  ditch. 

At  Junction  City,  Trinity  County,  California,  there 
has  been  laid  5700  feet  of  siphon  pipe  to  carry  the  water 
over  280  feet  depth  of  canon.  This  was  made  in  two 
sections:  2300  feet  is  No.  10  iron,  30  inches  in  diameter, 
and  3400  feet  is  No.  7  iron,  36  inches  in  diameter.1 

At  Cherokee,  Butte  County,  California,  an  inverted 
siphon  30  inches  in  diameter  is  used  to  cross  a  valley 
873  feet  deep.  This  siphon  pipe  was  nearly  2j  miles 
long,  and  was  the  first  large  siphon  used  in  hydraulic 
mining. 

Siphons  must  be  provided  with  expansion  joints;  be 
firmly  anchored  on  the  inclines  ;  have  suitable  air 
valves  ;  and  laid  with  great  care.  When  suitable  care 
is  -observed  in  jointing  and  laying  sheet-metal  pipes, 
they  will  be  as  serviceable  for  siphons  as  in  other 
hydraulic  pipe-line  situations. 

The  paper  presented  by  J.  W.  Phillips  on  "  Hydraulic 
Mining  of  Auriferous  Gravels,"  in  1910,  before  the  Society 
of  Western  Engineers  was  both  historical  and  valuable, 
1  Mining  and  Scientific  Press,  Nov.  27,  1897. 


206  LINES   AND    DITCHES 

not  alone  on  account  of  its  practical  worth  but  because 
it  drew  into  the  discussion  W.  B.  Storey,  Jr.,  who  was 
the  first  inspecting  engineer  under  the  Caminetti  Act  of 
1893,  and  others  who  had  spent  some  time  in  the  busi- 
ness. Ditch  building  has  progressed  from  a  mere  guess 
to  scientific  achievement.  The  first  miners  put  in 
ditches  to  carry  the  required  amount  of  water  and  few, 
if  any,  of  them  knew  how  to  figure  the  flow  of  water ;  hence 
they  worked  by  cut  and  try  methods,  but  finally  the 
judgment  of  an  old  and  experienced  miner  became 
wonderful  on  the  subject  of  grades  and  quantity  of  water. 
Crude  methods  of  measuring  water  flowing  through 
orifices  under  a  head  were  developed  and  the  amount  of 
water  was  the  area  in  square  inches  regardless  of  shape. 
Following  the  first  miners,  came  a  new  generation  of 
men,  many  of  them  engineers  and  surveyors,  who  used  the 
following  adaptation  of  formulae  to  open  ditches: 


Eytelwein,    v  =  \/(gooors  +  0.012)  —  o.n. 

,  //oooo  as\ 
Poncelot,      i)  =  y  \^—L — )  -  o.i i. 


And  for  pipes  the  formula    v  =  48  y  — 


As  the  mines  grew  larger  the  engineers  became  more 
expert  and  a  credit  to  their  profession.  The  classic 
experiments  of  Hamilton  Smith  on  the  flow  of  water  in 
pipes  were  made  for  hydraulic  miners. 

Early  miners  gave  the  ditches  such  steep  grades  that 
the  bottoms  were  eroded,  so  that  now  some  of  the  old 
abandoned  ditches  have  dug  ravines.  Mr.  Phillips 


DITCH  TELEPHONE  LINES  207 

advises  the  use  of  Sir  John  Neville's  figures  for  safe  veloci- 
ties in  canals  which  are: 

In  sift  alluvial  0.42  ft.  per  sec. 

In  clayey  soils  0.67  ft.  per  sec. 

Sandy  and  silt  beds  i.oo  ft.  per  sec. 

Gravelly  earth  2.00  ft.  per  sec.' 

Shingly  soil  4.00  ft.  per  sec. 

Shingly  and  rocky  5.00  ft.  per  sec. 

Over  rocky  formations  6.67  ft.  per  sec. 

The  Dubuat  formula  for  bottom  velocity  is 

Vb  =  v  —  ii  Vrs, 
in  which 

Vb  =  bottom  velocity  in   t.  per  sec. ; 
v  =  mean  velocity  in  ft.  per  sec.; 
r   =  mean  hydraulic  radius; 
5  =  sine  of  the  slope. 

Where  the  snowfall  is  excessive  or  the  ditches  wash  out 
or  are  occasionally  filled  by  a  landslide,  patrol  stations  are 
provided  at  intervals  of,  say,  five  miles  along  the  ditch. 

A  telephone  system  is  then  established  between  the 
stations  and  the  general  offices  in  order  to  save  time  in 
case  anything  goes  wrong  with  the  water  system.  Two 
men  patrol  the  ditch  and  telephone  line  each  day  making 
examinations  of  both  installments,  for  should  a  break  in 
the  ditch  occur  it  must  be  repaired  quickly,  otherwise  the 
plant  must  stop  work.  Should  any  change  in  conditions 
occur  during  the  night,  the  men  at  the  different  stations 
are  notified  through  the  ringing  of  an  electric  bell 
actuated  by  a  float  in  some  part  of  the  ditch  near  them. 
The  telephone  is  then  used  to  locate  the  position  of  the 
trouble  and  steps  immediately  taken  for  its  remedy. 


208  LINES   AND    DITCHES 

The  telephone  line  consists  of  a  single  wire  of  gal- 
vanized iron  about  No.  14  Birmingham  gauge  or  No.  12 
Brown  and  Sharpe  gauge.  This  size  of  wire  weighing 
about  100  pounds  to  the  mile  will  generally  answer  all  re- 
quirements provided  it  is  well  grounded  and  the  splices 
are  properly  made.  When  the  space  between  poles  is  200 
feet,  26  poles  are  needed  to  the  mile,  and  if  suitable 
wooden  poles  are  not  available  along  the  route,  wrought 
or  steel'  pipe  poles  are  recommended. 

Writing  from  experience  it  may  be  safely  stated  that 
one  cannot  make  telephone  lines  of  this  description  too 
good,  and  where  so  much  depends  on  the  line  it  is  false 
economy  to  scrimp  on  its  cost. 

The  poles  should  be  about  24  feet  in  length  so  that  at 
least  4  feet  may  be  placed  in  the  ground.  A  few  feet 
between  poles  either  way  is  better  than  trying  to  anchor 
a  pole  on  a  rock  with  braces,  and  will  be  found  cheaper 
in  the  end.  When  pipe  poles  are  adopted,  they  may  be 
made  of  two  sizes  of  pipe,  the  first  of  3-inch  pipe  filled 
with  cement  and  the  second  or  upper  section  coupled  to 
this  made  of  2-  or  2|-inch  pipe. 

When  it  becomes  necessary  to  span  gulches  or  to  in- 
crease the  distance  between  poles  they  should  have  more 
strength  as  ice  will  accumulate  on  the  wire  and  in  this 
condition  wind  will  add  much  more  to  the  strains  they 
are  obliged  to  carry. 

All  tree  branches  or  other  vegetation  likely  to  ground 
the  current  should  be  cut  away  from  the  wire,  and  at 
least  every  fifth  post  should  be  protected  by  a  lightning 
rod  made  of  wire  and  grounded  with  wet  earth  or  water. 
A  lightning  rod  not  so  grounded  is  worse  than  none.  W 


DITCH  TELEPHONE  LINES  209 

is  probable  that  a  telephone  line  such  as  outlined  will  cost 
from  $40  to  $75  per  mile  as  there  are  insulator  brackets 
and  possibly  hand  rock  drilling  before  the  installment  is 
complete.  Since  it  is  not  an  easy  matter  to  climb  a  pipe 
pole  it  is  customary  to  put  a  loop  in  the  wire  at  frequent 
intervals  so  that  the  line  may  be  tested  between  stations 
and  if  found  defective  repaired. 

The  looped  wire  must  not  come  in  contact  with  the  pole 
and  should  end  at  such  height  that  it  will  not  be  damaged 
by  marauders. 


CHAPTER  VII. 

GIANTS    AND    HYDRAULIC    ELEVATORS. 

Giants.  —  The  nozzle  from  which  a  stream  of  water  is 
projected  in  hydraulicking  is  called  a  giant. 

With  the  introduction  of  stovepipe  in  the  first  stages 
of  hydraulic  mining  it  was  found  necessary  to  use  a 
short  piece  of  canvas  hose  in  order  to  fasten  the  nozzle 
to  the  discharge  end  of  the  pipe.  This  was  succeeded, 
as  pressure  was  increased,  by  the  gooseneck,  a  flexible 
iron  joint  formed  by  two  elbows  working  over  each  other. 

The  improvement  on  this  arrangement  was  the  radius 
plate. 

The  Craig  Monitor  followed,  and  then  the  Fisher 
Knuckle  Joint.  Next  came  Hoskin's  Dictator,  and 
Hoskin's  Little  Giant,  which  at  least  has  given  the  nozzles 
a  name,  as  they  are  now  termed  "giants." 

The  Joshua  Hendy  Company,  San  Francisco,  make 
what  they  term  a  double  ball-bearing  giant,  while  Hos- 
kin's New  Hydraulic  Giant  has  various  improvements 
over  former  styles.  These  improvements  have  been 
gradual,  the  more  recent  having  increased  their  efficiency 
and  convenience.  Figure  66  represents  Hoskins'  New 
Hydraulic  Giant. 

The  lever  shown  on  the  end  is  for  moving  the  deflector, 
which  throws  the  stream  to  any  desired  angle  and  moves 
the  body  of  the  giant.  Horizontal  and  vertical  motions 


SPOUTING  VELOCITY  21 1 

are  made  with  one  joint,  and  this  joint  is  protected  so 
as  to  be  durable.  The  nozzle  butt  is  attached  to  the 
pipe  so  as  to  counteract  the  upward  movement  when 
working  under  great  pressure.  The  nozzle  is  balanced 
by  matching  the  notch  in  its  flange  with  a  corresponding 
one  in  the  flange  of  the  elbow.  Where  there  is  a  down- 
ward tendency  of  the  pipe,  owing  to  low  water  pressure 
or  small  nozzle,  use  is  made  of  the  balancing  attachment 
shown. 


FIG.  66. 

Practice  has  demonstrated  that  one  giant  with  a  large 
nozzle  is  better  than  several  with  smaller  nozzles.  The 
large  nozzle  proportioned  to  the  pressure  will  do  more 
work,  and  offers  the  economic  advantages  of  concentrat- 
ing the  work,  thus  lessening  the  expenses. 

The  nozzles  are  constructed  from  4  to  9  inches  inside 
diameter,  the  inlets  varying  from  7  to  15  inches  diameter 
to  correspond. 

To  find  the  spouting  velocity  from  a  nozzle  of  any 
diameter,  under  any  head  or  column  or  water  pressure, 


212          GIANTS  AND  HYDRAULIC  ELEVATORS 

and  the  amount  of  water  which  will  flow  per  second 
through  the  orifice,  proceed  as  follows :  — 

1.  Find  the  area  of  the  nozzle  in  square  feet. 

Area  in  square  feet  =  diameter  in  inches  X  diameter  in 
inches  X  0.7854  -5-  144. 

Example.  —  What  is  the  area  in  square  feet  of  i  J-inch- 
diameter  nozzle  ? 

1.25  X  1.25  X  0.7854  H-  144  =  0.0085. 

2.  Find  the  theoretical  velocity,  and  multiply  it  by 
0.80,  the  coefficient  of  friction  caused  by  the  rushing  of 
water  through  the  nozzle. 

Theoretical  velocity  =  VHead  in  feet  X  8.03. 
Actual  velocity          =  Theoretical  velocity  X  0.80. 

Example.  —  With  a  head  of  25  feet,  what  is  the  theo- 
retical and  what  the  actual  velocity  with  which  water  will 
spurt  from  an  orifice  ? 

Theo.  vel.     =  ^25  X  8.03   =  5  X  8.03  =  40.15. 

Actual  vel.    =  40.15  X  0.8=  32.12  feet  per  second. 

Application  to  rule. 

Question.  —  What  amount  of  water  will  flow  through 
a  ij-inch-diameter  nozzle  under  a  head  of  25  feet? 

Rule.  —  Area  in  square  feet  of  nozzle,  X  actual  veloc- 
ity in  feet  per  second: 
0.0085  X  32.12  =  0.273    cubic    feet    per   second  X  7.5 

=  2.0475  gallons  per  second. 

0.273  X  60  =  16.38      cubic     feet    per     minute  X  7.5 

=  122.85  gallons  per  minute. 
There  are  two  general  types  of  giants  in  use,  namely 


NOZZELS 


213 


the  single-  and  the  double-jointed.  The  single-jointed 
nozzle  is  probably  more  efficient  in  manipulation,  as  it 
can  be  lubricated  without  turning  the  water  out  of  the 
machine.  The  double-jointed  nozzle  has  the  advantage 
as  far  as  the  efficiency  of  the  stream  is  concerned; 
it  is  also  safer  to  handle  under  high  heads.  The  double- 
jointed  nozzle  without  a  king  bolt  has  a  clear  waterway, 


Pipeman. 

but  on  account  of  damage  to  its  ball  bearings  at  times, 
the  king-bolt  type  is  the  better.  The  giant  should  be 
set  securely  on  heavy  timbers  and  bolted  to  timbers  and 
the  timbers  to  rock  if  possible.  In  any  case  stakes 
should  be  driven  where  there  is  gravel  instead  of  rock, 
either  through  the  bed  piece  or  against  the  bed 
piece. 

The  nozzle  is  liable  to  "buck"  if  not  securely  anchored 
and  damage  both  the  pipe  man  and  the  attachments. 


214        GIANTS  AND  HYDRAULIC   ELEVATORS 

The  giant  must  be  lubricated  so  that  it  may  be  turned 
readily  by  the  deflector,  either  right  or  left  or  up  or  down. 
The  tendency  in  recent  practice  is  to  make  a  long  smooth 
nozzle,  and  thus  prevent  the  spraying  as  much  as  possible. 
In  order  to  obtain  the  best  results  from  any  nozzle,  air 
must  be  kept  out  of  the  pipe  line,  for  which  reason  the 
pressure  box,  the  air  valve,  and  the  standpipe  are 
adopted,  as  already  explained. 

Hydraulic  Elevators.  —  The  Evan's  gravel  elevator, 
which  is  herewith  illustrated  through  the  kindness  of 
the  Risdon  Iron  Works  Company,  is  used  for  disposing 
of  tailing  where  sufficient  fall  for  tail  sluices  is  not 
available,  or  where  it  is  impossible  to  run  bed  rock  sluices. 
Hydraulic  mining,  now  being  under  United  States 
supervision,  has,  as  before  mentioned,  received  new 
impetus  in  California,  where  a  demand  for  suitable 
machinery  necessary  to  overcome  obstacles  is  increasing; 
consequently,  this  machine,  like  the  improved  dredgers, 
comes  very  opportunely. 

The  principle  of  the  elevator  is  that  of  a  steam 
injector,  or  where  the  velocity  of  the  water  flowing  up 
through  an  orifice  is  sufficient  to  cause  a  vacuum  and 
hence  a  suction  through  a  tail  pipe.  It  is,  of  course, 
necessary  to  have  a  higher  head1  for  such  machines  than 
is  merely  necessary  to  lift  the  water  to  a  certain  height, 
for  friction  of  the  water  and  the  weight  and  friction  of 
the  gravel,  together  with  gravity  acting  upon  the  whole 
mass  of  water  and  gravel,  must  be  overcome. 

Besides  the  motive- power  pipe,  D,  Fig.  67,  there  are 
four  other  openings  in  this  elevator,  A,  B,  C,  E.  B 

1  About  five  times  the  head,  over  the  lift. 


Ft 


2i6         GIANTS  AND  HYDRAULIC  ELEVATORS 


and  C  are  termed  auxiliary  suctions,  which  allow  the 
water  and  material  to  enter  at  the  back  of  the  seat,  thus 
reducing  the  wear  and  tear  on  the  machine.  The 
auxiliary  suctions  can  have  their  tail  pipes  extended  to 
any  distance  beyond  the  elevator  proper,  as  shown  in 
the  page  cut,  and  thus  be  used  for  draining  bed  rock, 
below  the  sluice  connecting  with  the  main  elevator 
opening,  A.  This  may  be  very  advantageous  at  times, 
and  can  be  carried  on  without  interfering  with  the  main 
work  of  sluicing. 

The  auxiliary  openings  also  increase  the  efficiency  of 
the   elevator,  by   allowing    the    proper   amount    of  air 
and    material    to    enter   when    the 
main    suction,  A,    becomes  choked 
or  for  some  other   cause  is   unable 
to  do  its  duty. 

This  feature  economizes  water, 
which  must  otherwise  be  turned 
off  or  run  to  waste  while  the 
obstruction  is  being  removed  or  the 
difficulty  obviated. 

"Evans'  elevators  in  New  Zeal- 
and, with  less  than  400  miner's 
inches  of  water  (600  cubic  feet), 
under  a  head  of  225  feet,  lifted 


FIG.  67. 


sand  and  gravel  to  a  height  of  52  feet  at  the  rate  of  2400 
tons  in  24  hours." 

"  Other  similar  work  was  carried  on  for  years,  elevat- 
ing one  acre  of  ground  per  month,  varying  in  depth  from 
30  to  35  feet."  1 

1  Mr.  R.  S.  Moore. 


EVANS'    ELEVATOR  217 

The  elevator  to  accomplish  this  work  used  250  miner's 
inches,  and  raised  its  own  water,  the  water  coming  from 
the  giant  at  the  rate  of  1687.5  gallons  per  minute,  and 
the  material  the  giant  washed  out  to  it. 

The  expenditure  of  223  H.P.  to  accomplish  the  work 
of  74.5  H.P.,  thus  obtaining  but  an  efficiency  of  33}  per 
cent  of  the  power  expended,  does  not  at  first  glance  seem 
economical,  but  when  it  is  considered  that  47  per  cent 
of  the  power  is  used  by  the  water  in  raising  its  own 
weight  and  that  19 J  per  cent  is  employed  in  overcom- 
ing friction  the  machine  as  a  pump  becomes  satis- 
factory. 

Elevators  are  connected  so  as  to  be  permanent,  they 
may  be  arranged,  however,  so  as  to  do  their  own  sinking 
to  bed  rock,  a  commendable  feature,  when  it  avoids  the 
necessity  of  making  a  pump  by  hand,  which  may  require 
timbering  and  pumping  arrangements,  as  well  as  a  diver, 
to  connect  the  elevator. 

The  excavation  necessary  in  placing  a  1 6-inch  elevator 
at  the  Golden  Feather  River  Mine,  Oroville,  California, 
was  4  square  feet,  while  the  previous  year  an  old  style 
elevator  required  128  square  feet  of  excavation  and  the 
services  of  a  diver  to  place  it  in  position. 

The  Evan's  elevator  was  fitted  up,  lowered  to  the 
bottom  of  the  river,  and  set  at  work  in  twelve  hours' 
time. 

The  machines  could  be  proportioned  to  elevate  all  the 
gravel  which  one  giant  could  wash  and  sluice,  were 
the  material  of  a  proper  size  to  go  through  the  throat 
of  the  machine.  The  area  of  the  throat  will  depend  upon 
the  water  available,  and  should  be  proportioned  to  the 


218 


EFFICIENCY  OF  ELEVATORS  219 

average  size  of  the  stones  in  the  gravel  bank.  The  latter 
is  an  indeterminable  quantity,  consequently  screen  bars 
or  "grizzlies"  are  placed  in  the  sluice  to  allow  only  cer- 
tain-sized material  to  pass  through  into  the  sluice  going 
to  the  elevator.  Where  water  is  available  or  lift  slight 
the  throat  may  be  proportioned  to  accommodate  large 
stones;  the  largest  throat  on  record  is  for  stones  which 
will  pass  a  p-inch  screen. 

This  is  a  subject  of  much  significance,  for  the  object 
of  such  machines  must  be  in  part,  if  not  wholly  so,  to 
raise  the  greatest  amount  of  material  possible  from  the 
workings  and  put  it  out  of  the  way  once  and  for  all. 

Mining  men  thoroughly  understand  the  importance 
of  the  preceding  clause,  and  it  has  been  stated  to  the 
writer  that  since  the  introduction  of  the  Evans'  elevator 
mining  men  are  now  seeking  propositions  which  require 
an  elevator,  although  heretofore,  owing  to  heavy  cost, 
weight,  and  inefficiency  of  old-style  elevators,  they 
would  not  consider  them. 

Mines,  which,  with  former  crude  machinery,  were 
unable  to  pay  expenses,  have  by  the  use  of  these  new 
machines  been  turned  into  dividend  payers. 

There  are  two  instances  where  these  machines  have 
been  able  to  elevate  with  a  2|-inch  jet  from  the  motive- 
power  pipe  all  the  sand,  gravel,  and  water  it  was  possible 
to  bring  down  the  sluice  on  a  2  per  cent  grade.  The 
giant  had  a  2  J- inch  nozzle  and  used  1687.5  gallons  of 
water  per  minute,  while  the  elevator  used  3187.5 
gallons  of  water  per  minute,  and  raised  water  and 
material  52  feet.  The  highest  elevation  on  record  is 
70  feet. 


220        GIANTS  AND   HYDRAULIC  ELEVATORS 

The  Golden  Feather  Company,  who  are  very  large 
river  operators,  dammed  the  Feather  River  at  Oroville 
with  head  and  foot  dams  ij  miles  apart,  the  object 
being  to  work  the  gravel  in  the  bottom  of  the  river.  The 
river  at  this  place  is  between  two  and  three  hundred  feet 
wide  and  from  twenty  to  thirty  feet  deep.  In  order, 
therefore,  to  reach  this  gravel  bed,  wing  dams  were  made 
and  the  water  course  changed,  and  finally  the  water 
between  the  dams  pumped  out.  To  effect  the  latter, 
two  Evans'  elevators  were  set  at  work  and  accomplished 
the  pumping  in  2j  days.1 

The  data  required  for  estimating  the  duty  for  such 
elevators,  and  which  the  makers  require  are: 

1.  Quantity  of  water  available.  —  This  must  include 
the  amount  of  water  the  giant  will  use,  and  the  remainder 
will  only  be  available  for  the  elevator. 

2.  The  head  of  water  in  feet.  —  By  doubling  the  size 
of  a  nozzle  under  a  given  head  of  water  there  is  4  times 
the  quantity  of  water  passed  in  a  given  time,  while  with 
4  times  the  head  but  twice  the  quantity  is  passed  by  the 
same  nozzle. 

3.  The  distance  the  elevator  must  lift.  —  Usually  but  \ 
the  head  can  be  counted  upon,  the  head  being  used  up 
in  overcoming  friction  and  the  power  which  the  weight 
of  the  column  of  water  and  material  of  the  suction  pipes 
have  in  retarding  its  flow,  together  with  its  own  weight 
and  friction. 

4.  The  distance  from  bed  rock  to  the  top  of  bank.  — 
If  placed  on  the  bank  the  elevator  must  raise  a  column 

1  Risdon  Iron  Company. 


EFFICIENCY  OF  ELEVATORS  221 

of  water  and  material  equal  to  the  distance  between 
the  throat  and  the  level  of  the  water.  On  the  other 
hand,  if  on  bed  rock,  the  weight  of  water  and  mate- 
rial will  assist  the  elevator. 

5.   The  largest  size  of  gravel  to  be  elevated. 

There  are  three  hydraulic  elevators  in  the  market  the 
Hendy,  the  Evans,  and  the  Campbell,  the  latter  is  said 
to  be  adapted  to  higher  pressures  than  the  others,  and 
has  been  successfully  used  in  British  Columbia  and 
Alaska. 

Where  it  is  possible  to  obtain  water  under  pressure 
low-lying  placers  have  been  readily  worked  by  the  aid 
of  elevators.  To  attain  good  results,  however,  with  such 
apparatus  the  minimum  amount  of  water  should  elevate 
the  maximum  amount  of  gravel,  and  this  can  only  be 
attained  by  properly  proportioning  the  elevator  to  its 
pressure  and  lift.  The  velocity  of  the  water  in  the 
pipes  should  not  exceed  5  feet  per  second.  At  Breck- 
inridge,  Colorado,  there  are  two  elevators  working  gravel 
deposits  with  160  feet  head  and  lifting  the  material  42 
feet  above  bed  rock.  This  is  excellent  work,  as  a  20- 
foot  lift  to  every  100  feet  head  of  water  is  the  maker's 
rule,  and  in  hydraulic  practice  the  engineer  considers  a 
lift  of  15  feet  for  every  100  feet  head  sufficient  for  calcu- 
lations. Under  favorable  conditions  the  cost  of  work- 
ing elevators  is  5  cents  per  cubic  yard,  which  includes 
the  hydraulicking.  A  good  elevator  can  handle  from 
1000  to  2000  cubic  yards  of  dirt  in  24  hours,  provided 
it  is  supplied  in  a  reasonably  uniform  manner.  There 
is  another  elevator,  termed  the  Ludlum,  which  consists 
of  a  giant  nozzle  fastened  in  a  pipe  in  such  a  way  as  to 


222        GIANTS  AND  HYDRAULIC  ELEVATORS 

form  a  vacuum  in  the  throat  of  the  apparatus.  It  does 
not  differ  materially  in  details  from  those  mentioned, 
except  it  is  not  as  scientifically  constructed  and  is  simply 
a  round  pipe  affair.  It  can  do  fairly  good  work  and  has 
been  employed  to  some  extent. 

It  has  been  demonstrated  by  practice  that  the  rela- 
tionship between  the  quantity  of  water  used  and  the  drift 
removed  can  be  established  only  after  an  extended  period 
of  observation  and  operation. 

To  arrive  at  somewhat  definite  conclusions  regarding 
this  relationship  the  volume  of  water  used  by  the  eleva- 
tors and  giants  is  measured,  also  the  ground  removed 
during  the  time  the  giants  are  at  work. 

To  measure  the  quantity  of  ground  removed  during  a 
given  period  it  is  necessary  to  have  a  working  map  drawn 
to  a  scale  of  at  least  200  feet  to  the  inch  on  which  are  to 
be  located  boreholes,  pipes,  sluices,  elevators,  etc. 

Should  this  map  be  plotted  on  cross-sectional  paper 
with  squares  representing  100  square  yards  it  will  prove 
convenient  although  not  absolutely  necessary;  however, 
the  elevations  and  depressions  of  the  surface  should  be 
shown  on  any  working  map  by  contour  lines  taken  at 
intervals  of  five  feet  for  such  work. 

Various  methods  of  surveying  and  estimating  the 
quantity  of  gravel  bank  worked  away  by  water  are 
adopted  by  engineers  all  of  whom,  however,  it  is  believed 
make  use  of  horizontal  contours  in  estimating  yardage. 
These  surveys  and  estimates  are  made  monthly  or 
quarterly,  preferably  the  former,  as  closer  watch  may  then 
be  kept  on  the  work  which  is  an  object  when  water  is 
scarce. 


SURVEY  OF  PROGRESS  223 

When  making  a  survey  to  ascertain  the  progress  of 
hydraulicking  some  known  point  near  the  bank  is  selected 
where  the  transit  set  up  can  be  sighted  to  various  points 
and  can  measure  the  elevation  or  depression  angle  at 
each  point  of  the  face. 

To  obtain  the  distances  stadia  measurements  are  taken 
and  with  this  data  the  true  levels  and  horizontal  dis- 
tances are  calculated  and  plotted  on  the  map.  Points 
for  contour  lines  are  interpolated  between  those  taken  in 
this  survey  and  those  previously  taken  and  placed  on  the 
map  at  five-foot  intervals. 

The  corresponding  lines  from  a  previous  survey  are 
left  on  the  map  and  the  area  removed  at  each  level  calcu- 
lated by  a  planimeter. 

Areas  and  depths  being  thus  found  the  volume  of 
the  earth  removed  is  calculated  by  simple  multiplica- 
tion. 

At  those  mines  where  the  bank  breaks  some  distance 
back  from  the  face  and  gradually  but  continually  moves 
towards  the  giants,  the  surface  of  the  ground  changes  so 
quickly  in  depth  that  a  rapid  survey  and  calculation  is 
advisable.  To  measure  the  progress  of  the  slide  two  or 
three  rod  men  are  employed,  and  the  transit  located  at 
a  convenient  place  by  taking  bearings  to  several  objects 
that  have  been  placed  correctly  on  the  map. 

The  lines  of  sight  to  these  objects  converge  at  the 
transit.  Stadia  measurements  and  angle  elevations  are 
then  taken  in  the  usual  way  calculated  and  marked  on 
tracing  cloth.  The  tracing  cloth  with  the  lines  converg- 
ing relative  to  the  position  of  the  transit  is  laid  on  the 
map  and  shifted  until  the  lines  coincide  with  the  objects 


224        GIANTS    AND    HYDRAULIC   ELEVATORS 

previously  selected  when  the  transit  station  is  pricked 
through  onto  the  map.  From  this  point  to  the  ace  the 
survey  is  marked  on  the  map  in  the  usual  manner. 

E.  B.  Tinker,  Chief  Engineer  of  the  Miami  Copper 
Company,  devised  a  stadia  chart  whose  object  is  to  do 
away  with  the  tables  and  calculations  required  in  reducing 
stadia  data  to  measurements.  By  the  use  of  this  chart 
the  work  becomes  merely  a  mechanical  adjustment  of  a  T 
square  and  the  reading  of  coordinates.  Any  angle  up  to 
45°  being  required,  by  simply  sliding  a  T  square  as  di- 
rected will  give  both  the  vertical  and  horizontal  meas- 
urements for  the  distances  and  the  angle,  at  the  same 
time.  The  Chart  is  patented  and  sold  by  the  Technical 
Supply  Company  of  Scranton,  Pa. 

Having  explained  the  method  of  measuring  the  bank, 
attention  is  next  directed  to  measurement  of  the  water 
as  its  spouts  from  the  giant. 

The  discharge  from  giants  or  the  nozzles  of  hydraulic 
elevators  is  estimated  by  taking  the  product  of  the  jet 
area  #,  the  mean  jet  velocity  v,  and  a  coefficient  of  dis- 
charge k.  If  W  =  the  water  used  then 

W  =  kav. 

Experience  has  shown  that  owing  to  the  vena  con- 
tracta,  and  possibly  to  some  interference  of  the  at- 
mosphere, the  theoretical  velocity  of  the  water  is  too 
high  and  consequently  the  coefficient  or  factor  is  taken 
at  94  per  cent  of  the  theoretical.  Expressing  the  area  by 

TT^2  .7854  & 

a  =  —   =  -         -  =  .00546  d? 

4  X  144          144 


MINER'S  HEAD  DAY  225 

and  the  velocity  by  v  =  V2gh  =  8.03  Vh,  then  substi- 
tuting these  values  in  the  equation  above 

W  =  .94  X  8.02  Vh  X  .005  d2  =  .03774  d2  Vh. 

The  quantities  of  water  are  so  large  that  the  amounts 
if  expressed  in  gallons,  cubic  inches  or  miner's  inches  are 
inconvenient,  for  which  reason  the  "miner's  head"  or  the 
equivalent  of  100  miner's  inches  is  advanced,  that  is  a 
miner's  head  is  100  miner's  inches  or  150  cubic  feet  of 
water  per  minute,  9000  cubic  feet  per  hour  or  216,000 
cubic  feet  per  "miner's  head  day."  Making  use  of  these 
quantities  in  the  equation 


W  =  .03774  d2  Vh  x  ~^-  =  .0943  d2  Vh  miner's  heads, 
oo 

which  is  readily  reduced  to  miner's  inches.  To  measure 
-the  water  pressure  gauges  are  provided  at  each  nozzle 
and  the  pressure  is  read  every  shift,  or  when  there  is  any 
change  in  the  size  of  the  nozzle. 

After  an  extended  period  of  regular  water  measure- 
ments at  the  nozzle  and  the  gravel  moved  calculated 
during  the  period  it  will  be  found  that  there  is  a  relation 
between  them  and  the  grade  of  the  sluice,  but  that  a 
coefficient  must  be  introduced  to  make  any  sort  of  a 
working  formula. 

For  this  purpose  let  D  =  cubic  yards  of  dirt  moved; 
W  =  cubic  yards  of  water  used  to  move  the  dirt;  and 
g  =  average  grade  of  the  sluice.  Then: 

D  =  kW  sin  g. 
One  miner's  head  day  is  equal  to  8000  cubic  yards  of 


226        GIANTS   AND   HYDRAULIC   ELEVATORS 

water  and  the  amount  of  ground  moved  daily  is  expressed 
by  D  =  8000  k  sin  g. 

The  value  of  k  may  be  taken  as  .98  for  loose  drift 
free  from  hard  pan,  and  boulders;  as  .85  for  hard  pan; 
and  for  hard  pan  and  boulders  it  may  be  taken  as  .80. 
An  example  from  actual  practice  is  given  where  the  ma- 
terial contained  some  clay  but  was  otherwise  so  clean, 
the  value  of  k  =  .95  was  assigned  to  it.  The  water  used 
during  the  period  of  investigation  amounted  to  90  miner's 
head  days,  while  the  grade  of  the  sluice  was  i  in  24.  This 
data  when  substituted  in  the  equation  gives: 

D  =  8000  X  90  X  .95  X  2*¥  =  28,500  cubic  yards. 

The  amount  of  dirt  removed  was  estimated  by  survey  to 
be  28,587  cubic  yards. 

It  will  be  found  from  this  data  that  it  required  25.4 
parts  of  water  to  move  i  part  of  ground. 

This  may  be  considered  indifferent  practice  compared 
with  the  La  Grange  in  California  where  11.5  parts  of 
water  removed  i  part  of  dirt.  At  some  places  where  there 
is  an  abundance  of  water,  it  is  allowed  to  run  over  the 
bank  and  to  the  sluice.  The  little  erosion  that  such 
waterfall  mining  accomplishes  is  hardly  worth  while, 
and  it  is  good  policy  to  confine  this  water  even  if  the  fall 
is  not  great,  for  if  piped  to  the  face  with  a  giant  it  will 
accomplish  much  more  work. 

The  more  power  a  stream  of  water  possesses  the  more 
disintegrating  work  it  will  perform,  and  a  small  stream 
of  water  spurting  from  a  nozzle  under  pressure  erodes  a 
bank  of  earth  much  more  quickly  than  a  large  stream  of 
water  flowing  over  it  under  no  pressure. 


CHAPTER  VIII. 

EXPLOITING    PLACERS. 

Placer  Mining  Investments.  —  People  have  invested 
in  placer  mines  under  the  impression  that  all  that  was 
necessary  was  to  dig  the  dirt,  and  the  water  would  save 
the  gold.  They  were  not  aware  that  assays  that  included 
black  sands  were  not  to  be  relied  on,  as  the  gold  in  black 
sands  can  not  be  saved  by  hydraulicking.  They  were 
not  aware  that  fine  gold  could  not  be  saved  with  any 
reasonable  degree  of  surety,  nor  did  they  take  into  con- 
sideration the  fact  that  there  are  tricks  in  all  trades. 
It  never  seems  to  occur  to  such  individuals  that  mining 
is  a  science,  and  that  to  be  proficient  in  that  science  one 
must  have  both  the  experience  and  the  the  theory  of  the 
subject  at  command.  If  a  person  purchases  real  estate, 
he  hires  a  lawyer  to  examine  the  titles;  if  he  wants  his 
teeth  fixed  he  goes  to  the  dentist;  if  he  is  sick  he  calls 
on  a  physician;  but  when  he  goes  into  mining  he  takes 
the  word  of  any  plausible  talker ;  and  invests  his  money  on 
the  strength  of  a  report  made  by  a  stranger.  He  assumes 
that  mining  is  a  gamble  and  that  the  successful  mine 
investor  struck  luck.  This  is  not  the  case,  and  he  will 
find  on  enquiry  that  the  successful  mine  owner,  hires  a 
mining  engineer  who  has  a  reputation  to  sustain  as  a 
careful  and  reliable  man  in  his  profession. 

There  have  been  many  failures  in  placer- mining 

227 


228  EXPLOITING  PLACERS 

ventures,  some  of  which  were  due  to  the  lack  of  gold, 
or  to  the  gold  being  so  fine  it  could  not  be  saved,  while 
other  failures  were  due  to  the  incompetency  of  the  man- 
agement. A  mining  engineer,  versed  in  the  details  that 
enter  into  the  successful  operation  of  placer-mining, 
has  never,  to  the  writers  knowledge,  failed  in  this  busi- 
ness, for  which  reason  a  mining  engineer  of  some  repu- 
tation should  be  retained  as  consulting  engineer  until 
the  business  is  on  a  paying  basis. 

Water  Required  for  Hydraulicking.  —  The  quantity 
of  water  required  for  washing  dirt  must  be  determined 
in  a  measure  by  the  kind  of  gold  in  the  dirt.  Clear, 
sandy  'gravel  will  not  require  as  much  water  as  clay  or 
cement  gravel,  and  it  is  possible  to  use  too  much  water 
in  clay  washing. 

The  size  of  a  sluice  depends  upon  the  grade  and  kind 
of  the  gravel,  also  upon  the  water  used  and  its  duty. 
The  duty  varies.  From  the  large  amount  of  data  re- 
ceived and  tabulated  by  Mr.  Bowie  there  is  nothing 
absolute  which  can  be  placed  as  a  rule,  therefore,  close 
observation  must  determine  the  quantity.  According 
to  Mr.  Hall,  of  California,  3.6  cubic  yards  of  dirt  were 
moved  by  1.5  cubic  feet  of  water,  for  24  hours'  duration; 
this  is  equivalent  to  2160  cubic  feet  of  water  to  move 
97  cubic  feet  of  gravel,  or  22  cubic  feet  of  water  to  move 
i  cubic  foot  of  material.  A.  J.  Bowie  has  tabulated 
1 8  cubic  feet  of  water  to  move  i  cubic  foot  of  gravel  at 
North  Bloomfield,  and  56  cubic  feet  of  water  to  move 
i  cubic  foot  of  gravel  at  La  Grange  mines.  In  the 
former  instance  the  grade  was  8  per  cent  and  the  gravel 
light;  in  the  latter  place  the  grade  was  2  per  cent  and 


THE  VALUE  OF   PLACERS  229 

the  gravel  the  run  of  the  bank.  At  North  Bloomfield 
the  sluices  were  6  feet  wide  by  32  inches  deep;  at  La 
Grange  they  were  4  feet  wide  and  30  inches  deep.  The 
height  of  the  banks  varied  from  100  to  265  feet  at 
North  Bloomfield,  and  from  10  to  80  feet  at  La  Grange, 
a  difference  that  would  exert  considerable  influence  upon 
the  quantity  of  material  the  water  could  come  in  con- 
tact with,  and,  therefore,  mine. 

The  Cost  of  Hydraulicking.  —  The  yield  of  the  gravel 
at  North  Bloomfield  was  7.75  cents  per  cubic  yard, 
the  cost  of  mining  4.1  cents  per  cubic  yard.  The  yield 
per  cubic  yard  of  gravel  at  La  Grange  was  10.19  cents, 
the  cost  of  mining  6  cents  per  cubic  yard-  The  cost  of 
mining  at  these  two  mines  would  analyze  about  as 

follows: 

Labor 60  per  cent 

Supplies 17  per  cent 

Water 13  per  cent 

Office 10  per  cent 

Ground  carrying  3.99  cents  per  cubic  yard  has  been 
worked  at  a  profit  at  North  Bloomfield.  With  such  a 
small  margin  to  work  on  it  is  evident  that  skill  and 
executive  ability  must  be  provided  from  the  pipeman  up. 

In  Idaho  a  placer  having  less  value  than  2  cents  per 
cubic  yard  has  been  worked  at  a  profit  when  others 
much  richer  have  proved  failures. 

In  the  Seward  Peninsula,  where  the  gold  is  coarse  and 
the  water  cold,  no  mercury  is  used  in  the  sluice-boxes, 
hence  all  fine  gold  passing  through  the  short  sluice  is 
wasted.  That  mercury  can  be  used  to  advantage  under 
these  adverse  circumstances  has  been  proven.  In  most 


230  EXPLOITING  PLACERS 

placer-mines  where  sluicing  is  practiced  mercury  is 
considered  to  be  one  of  the  most  potent  factors  in  col- 
lecting the  gold.  It  must  be  used  with  judgment,  how- 
ever, otherwise  it  will  be  lost,  and  amalgam  as  well. 
Under  the  most  favorable  circumstances  there  will  be 
a  slight  loss  of  mercury,  which  will  vary  according  to 
the  length  of  the  sluice,  and  the  care  used  in  charging 
the  riffles. 

Charging  the  Sluices.  —  Before  mercury  is  placed  in 
the  sluice  riffles,  dirt  and  water  is  allowed  to  run  through 
the  boxes  for  several  hours.  Too  much  water  should 
not  be  run  since  the  object  is  to  pack  the  sluice  and 
prevent  leakage,  and  this  can  be  best  accomplished 
by  the  water  and  material  moving  slowly  in  the 
sluices.  After  packing  has  been  accomplished,  the 
water  is  turned  off,  mercury  is  poured  into  the  riffles 
at  the  head  of  the  sluice,  and  afterwards  in  all  the 
riffles  and  undercurrents  on  the  line.  The  head  riffles 
are  charged  with  more  mercury  than  those  further  down 
the  line  since  they  will  have  more  gold  in  contact  with 
the  mercury.  The  quantity  of  mercury  to  use  in  a 
sluice  depends  upon  the  quantity  and  kind  of  gold  to 
be  saved,  and  upon  the  length  of  the  sluice.  An  1800- 
foot  sluice  was  charged  with  900  pounds  of  mercury, 
while  150  pounds  or  two  flasks  are  considered  sufficient 
for  a  240-foot  sluice.  Mercury  should  not  be  strained 
through  a  cloth,  or  spattered  in  pouring  into  the  riffles, 
but  should  be  poured  from  a  cow's  horn,  the  small  end 
of  which  is  sawed  off  so  as  to  be  opened  and  closed  with 
the  finger.  If  care  is  not  taken  in  charging,  little  globules 
of  mercury  will  be  formed,  and  these  will  float  away. 


CHARGING  THE  SLUICES  231 

There  are  times  when  mercury  becomes  sluggish  in  its 
action  owing  to  the  impurities  in  the  dirt,  or  to  the 
quantity  of  gold  it  has  amalgamated.  Such  mercury 
needs  quickening  by  the  addition  of  fresh  mercury  in 
small  quantities,  and  this  is  accomplished  by  com- 
mencing at  the  top  of  the  sluice  and  adding  about  4 
pounds  to  the  first  50  feet;  the  next  day  adding  3.5 
pounds  to  the  next  50  feet,  and  so  on  until  the  end  is 
reached,  when  the  head  of  the  sluice  is  again  charged. 
Some  charge  every  alternate  50  feet  daily,  but  this  is 
a  matter  that  must  be  decided  by  the  amalgamator  who 
examines  the  mercury  in  the  rifHes  with  his  fingers,  and 
from  its  condition  of  pastiness  judges  its  need  of  quick- 
ening. 

Before  mercury  is  placed  in  a  sluice  box  it  should  be 
cleaned,  and  the  best  method  of  doing  this  is  by  retort- 
ing. Some  use  sodium  or  cyanide  of  potassium  for 
cleaning;  however,  these  chemicals  are  not  so  effective 
as  the  retort.  If  the  mercury  becomes  foul,  a  clean-up 
should  be  made  as  soon  as  possible  and  the  mercury 
retorted.  The  condition  of  the  mercury  can  be  ascer- 
tained by  panning  the  sand  from  either  a  bafHe  board 
riffle  or  from  the  end  of  the  sluice.  When  panning,  a 
clean  iron  pan  should  be  used,  or  one  that  has  been 
thoroughly  burned  out  to  remove  any  mercury  that  may 
have  been  left  in  it  from  a  previous  panning.  These 
remarks  are  more  applicable  to  a  small  than  a  large 
operation,  since  the  latter  may  not  be  cleaned  up  for  j, 
whole  season,  consequently  the  loss  of  amalgam  and 
quicksilver  will  be  considerable,  even  although  fresh 
quicksilver  is  added  daily.  On  the  supposition  that  if 


232  EXPLOITING   PLACERS 

mercury  is  freed  at  the  top  of  the  sluice  it  will  be  caught 
later  on,  long  sluices  are  always  economical;  in  fact, 
there  was  less  loss  of  mercury  in  an  1800- foot  sluice  than 
in  a  36o-foot  sluice;  however,  the  two  sluices  were  not 
carrying  the  same  kind  of  dirt.  Where  sluices  are  too 
short,  and  the  grades  too  high,  or  the  sluices  poorly 
constructed,  or  the  ground  washed  contains  much  clay, 
talc,  or  other  impurities,  the  loss  of  gold  and  mercury 
may  amount  to  from  10  to  40  per  cent. 

If  there  are  undercurrents  in  the  sluice  line  they  are 
charged  at  the  same  time  the  sluice  boxes  are  given 
mercury,  the  quantity  depending  upon  the  width  and 
length  of  the  undercurrent.  A  good  saving  of  gold  by 
sluicing  depends  upon  the  skill  of  the  operator,  and 
may  be  placed  at  from  70  per  cent  up.  This  has 
reference  to  free  gold  where  conditions  are  favorable  for 
sluicing. 

The  Clean-up.  —  After  the  formation  of  amalgam, 
which  is  brittle  compared  with  mercury,  according  to 
the  amount  of  material  it  has  absorbed,  there  is  danger 
of  loss  by  its  floating  away,  and  this  means  a  loss  of  mer- 
cury and  gold. 

To  avoid  this,  "clean-ups,"  or  a  collection  of  the 
mercury,  gold,  and  amalgam,  should  take  place  as 
frequently  as  possible. 

The  cleaning-up  process  may  take  place  in  sections 
or  the  entire  length  of  the  sluice,  commencing  by  washing 
out  the  bed-rock  tunnel  or  the  ground  sluice  with  water, 
taking  up  their  pavements,  then  washing  the  blocks  and 
floor  of  the  sluice  boxes  down  to  the  first  riffle.  At  this 
latter  point  all  amalgam  and  gold  washed  down  is  taken  up 


CLEANING  UP  233 

with  an  iron  scoop  and  placed  in  an  iron  pail.  The  next 
section  of  sluice  floor  is  now  removed  and  treated  the 
same  way,  until  that  portion  of  the  sluice  to  be  cleaned 
up  has  been  gone  over.  The  little  water  which  was  used 
to  wash  the  blocks  is  now  turned  off,  and  the  cleaning  of 
the  cracks  and  nail  holes,  termed  "crevicing,"  is  com- 
menced by  using  silver  spoons,  to  which  the  mercury 
and  amalgam  cling.  This  process  having  been  gone 
through,  the  blocks  are  put  back  into  the  sluice  and 
gravel  washing  commenced  once  more.  The  time  occu- 
pied in  cleaning  up  will  depend  upon  the  number  of  men 
put  at  it.  Within  200  feet  of  the  head  of  the  sluice 
probably  three-fourths  of  all  the  gold  will  be  found; 
but  smaller  quantities  will  be  found  nearly  to  the  tail 
sluice,  depending  upon  the  nature  of  the  dirt  washed  and 
the  kind  of  gold.  The  tail  sluices  are  cleaned  up  only 
at  the  end  of  the  season.  The  amalgam  collected  is  now 
retorted  and  the  quicksilver  distilled  from  the  bullion  is 
collected. 

Certain  quantities  of  quicksilver  will  be  lost  in  the 
sluices  and  in  distillation.  In  the  first  instance  the  loss 
will  be  directly  proportional  to  the  quantity  of  water 
used  and  material  washed,  the  grades  being  the  same. 
If  clean-ups  occur  within  reasonable  periods  the  length 
of  the  sluice  will  not  be  a  factor,  but  otherwise  it  must 
be,  in  catching  fouled  mercury  or  amalgam  particles. 
There  is  no  method  of  determining  the  actual  loss  of 
gold,  because  there  is  no  way  of  arriving  at  the  absolute 
amount  of  gold  in  the  deposit;  it  is,  however,  a  certain 
percentage  of  the  gold  content. 

The  bed  rock  is  cleaned  by  allowing  a  stream  of  water 


234  EXPLOITING  PLACERS 

to  run  through  the  channel  until  it  is  clear.  Muddy 
water  is  said  to  aid  in  cleaning  gold  from  the  bed  rock; 
however  that  may  be,  clear  water  is  preferred,  and  cre- 
vicing  may  be  needed  in  seamy  rock  to  get  the  gold  from 
cracks.  When  the  bed  rock  is  clean  and  the  water  runs 
clear  through  the  sluices,  the  large  volume  of  water  is 
turned  off,  and  a  i-inch  rubber  hose  without  nozzle  used 
to  wash  down  the  blocks  as  they  are  taken  up.  The 
water  should  not  be  under  much  pressure,  and  in  a  wide 
sluice,  from  4  to  6  feet,  a  hose  on  each  side  would  mate- 
rially hasten  matters.  The  blocks  as  they  are  washed 
are  placed  on  the  sides  of  the  flume.  The  hose  may 
now  be  used  to  wash  down  the  material  on  the  bottom  of 
the  flume,  or  the  material  may  be  loosened  with  hoes  and 
shovels,  and  about  2  inches  of  water  let  in  for  the  same 
purpose. 

One  row  of  blocks  is  left  at  convenient  distances  apart 
in  the  sluice  in  order  to  hold  back  the  mercury,  gold,  and 
amalgam,  and  as  much  as  possible  is  taken  out  at  this 
place.  These  blocks  are  next  removed  and  washed,  after 
which  operation  the  washing  of  the  sluice  floor  is  con- 
tinued to  the  next  section,  and  so  on.  When  the  opera- 
tion is  finished  the  clean-up  gang  dig  the  amalgam  out 
of  nail  holes  and  crevices,  and  after  this  has  been  accom- 
plished the  blocks  are  replaced.  In  some  cases  there  is 
a  clean-up  every  20  days,  in  others  once  in  two  months, 
and  again  in  ground  sluices  but  once  a  season. 

Small  operators  will  probably  clean  up  every  week. 
It  is  probable  that  all  operators  should  clean  up  when 
their  floor  lining  commences  to  wear  in  grooves,  and  if 
large  operators  cannot  afford  to  do  this  on  account 


RETORTING  MERCURY  235 

of  their  water  supply,  they  can  at  least  clean  up  a  part 
of  their  sluices  daily  and  run  at  night. 

Amalgam  kettles  made  of  ordinary  sheet  iron,  or  better 
yet,  cast  iron  kettles  porcelain  lined,  are  used  as  recepta- 
cles for  the  clean-up.  The  quicksilver  and  amalgam  are 
stirred  in  these  kettles  in  order  to  separate  the  sand  and 
other  foreign  substances  which  float  to  the  surface  of  the 
mercury  and  are  there  skimmed  off.  (In  a  clean-up  in 
North  Carolina,  nails,  pennies,  and  quantities  of  bird  shot 
were  found.)  The  remainder  of  the  residue  contains 
considerable  amalgam  and  some  sand,  and  this  is  worked 
up  in  a  pan  or  rocker  until  concentrated.  The  concen- 
trate is  then  ground  in  iron  mortars  with  some  quick- 
silver, and  strained,  the  dry  amalgam  being  treated  in 
iron  retorts. 

Retorting  the  Mercury.  —  Where  an  operation  is 
small  and  the  clean-up  takes  place  frequently,  a  small 
retort  with  a  pipe  nozzle  can  be  used  advantageously. 
In  such  cases  there  may  be  no  necessity  for  straining  off 
the  mercury,  and  the  amalgam  and  mercury  may  be 
charged  into  the  retort  together.  The  retort  should  be 
well  chalked  inside,  with  a  clay  lute  to  the  cover,  and  the 
nozzle  of  the  pipe  should  be  immersed  in  a  pail  of  water. 
With  this  arrangement,  if  there  is  no  condenser,  the  pipe 
should  be  wrapped  with  gunny  sack,  and  a  stream  of 
water  allowed  to  run  over  the  sack  into  the  pail.  By 
watching  the  end  of  the  pipe,  it  is  possible  to  see  when 
the  last  of  the  mercury  has  left  the  retort,  and  when  this 
takes  place  the  retort  is  lifted  from  the  fire  and  gradually 
allowed  to  cool  before  the  cover  is  removed.  The  gold 
will  be  found  in  the  retort  in  an  impure  condition 


236 


EXPLOITING  PLACERS 


Where  large  quantities  of  amalgam  are  to  be  retorted 
bricked-in  retorts  similar  to  that  shown  in  section,  Fig. 
68,  are  used.  These  are  made  of  cast  iron  with  a  movable 
cover  at  the  back  end  and  connected  by  a  pipe  with  a 
condenser.  The  heat  from  the  furnace  passes  over  and 
.under  the  retort  and  makes  its  exit  through  a  suitable 
flue.  The  flue  must  be  the  entire  length  of  the  retort  so 
that  the  heat  will  be  uniformly  distributed. 

Before  putting  the  amalgam  into  the  retort  the  latter 


FIG.  68. 


should  be  coated  on  the  inside  with  a  thin  shee  of  clay 
to  prevent  the  amalgam  from  adhering  to  the  iron.  The 
amalgam  should  then  be  carefully  introduced  and  spread 
evenly.  The  pipe  connecting  the  retort  with  the  con- 
denser must  be  cleared  of  all  obstructions  and  the  amal- 
gam should  be  so  spread  that  by  no  possible  mischance 
can  this  pipe  become  choked,  as  an  explosion  would 
probably  result  and  fill  the  retorting  room  with  the 
poisonous  fumes  of  mercury.  To  avoid  danger  the 
heating  should  be  very  slow  at  first.  After  the  cover  has 


DRIFT  MINING 


237 


been  put  on  with  a  luting  of  clay  and  securely  clamped, 
the  fire  is  lighted  and  the  heat  is  gradually  raised  to  a 
dark  red,  that  temperature  being  all  that  is  necessary  to 
volatilize  the  quick- silver.  Toward  the  end  of  the 
operation,  the  heat  is  raised  to  a  cherry  red  until 
distillation  ceases.  The  retort  is  then  allowed  to  cool, 
and,  when  cold,  is  opened.  During  the  operation,  the 
condensing  coil  is  kept  cool  by  a  continuous  supply  of 
fresh  water  entering  at  the  lower  end  of  the  cylinder 
that  surrounds  the  coil,  while  the  discharge  of  warm 
water  takes  place  at  the  upper  end.  The  retort  bullion 


FIG.  69. 

is  cut  or  broken  in  to  pieces  and  melted  in  an  annealed 
black  lead  crucible  and  the  gold  cast  into  bars. 

Drift  Mining.  —  In  California,  placer  deposits  have 
been  formed  by  ancient  rivers,  and  these  rivers  were 
afterwards  made  the  beds  of  lava  streams  that  com- 
pletely capped  the  placers  as  shown  at  a  in  Fig.  69. 
Where  the  deposits  are  deep  and  wide  tunnels,  d,  are 
driven  through  the  rim  rock,  c,  to  strike  just  below  the 
center  of  the  ancient  river  bed,  b.  The  object  of  this 
tunnel  is  to  drain  the  deposit  and  to  transport  the  ground 
to  the  valley  where  it  may  be  sluiced.  Such  tunnels 
may  vary  from  one  quarter  of  a  mile  to  a  mile  in  length, 
depending  upon  the  width  of  the  deposit  and  the  thick- 


EXPLOITING  PLACERS 


ness  of  the  rim  rock.  Care  must  be  exercised  in  giving 
them  the  proper  grade  for  drainage.  If  the  tunnel 
should  be  driven  so  as  not  to  end  at  R,  but  to  strike  the 
deposit  higher  up,  its  object  would  be  only  partially 
successful. 

At  R  another  tunnel  is  driven  in  d  under  the  river 
bed  at  right  angles  to  d,  and  at  distances  of  120  feet  apart 
risers,  r,  Fig.  44,  are  put  up  to  the  deposit  for  the  purpose 


FIG.  70. 

of  drainage  and  to  act  as  chutes  for  the  mined  ore. 
From  these  mill  holes,  levels  are  driven  right  and  left  in 
the  deposit  until  the  rim  rock  is  reached.  A  second  tun- 
nel, a,  Fig.  70,  parallel  to  the  one  in  bed  rock,  is  driven 
in  the  deposit,  in  order  that  air  may  circulate  in  the 
different  workings,  and  in  addition  to  this,  breakthroughs, 
bt  between  two  parallel  cross  levels,  c,  are  made  at  stated 
intervals  as  shown  in  the  plan.  Every  60  feet  on  the 
cross  levels  rooms  are  turned,  and  thus  the  number  of 
working  faces  are  increased.  When  the  cross  levels 


DRIFT  MINING  239 

reach  the  rim  rock  the  pillars,  p,  are  driven  through  until 
they  are  cut  up  into  small  pillars,  e.  These  cannot  be 
recovered  readily,  and  are  left,  unless  they  carry  so  much 
gold  that  it  will  pay  to  timber  or  to  adopt  either  the 
caving  method,  as  practiced  in  iron  mining,  or  long 
wall  mining  as  practiced  in  coal  mining.  In  the  rooms 
single  posts  mounted  on  plank  sills  and  furnished  with 
plank  cap  pieces  are  used  for  holding  up  the  gravel. 
In  the  levels  four-stick  timbering  with  lagging  is  used 
to  support  the  excavation,  for  if  the  levels  close  the 
work  must  be  abandoned  until  new  levels  are  driven. 

It  is,  of  course,  understood  that  before  drift  mining  is 
undertaken  there  must  be  prospecting  done  to  ascertain 
the  value  of  the  deposit,  and  whether  the  returns  will  be 
more  than  the  expenses  incurred,  to  drive  tunnels  in 
rock,  timber  levels  in  gravel ;  mine,  gravel  and  transport  it 
to  the  sluice  box  at  the  mouth  of  the  tunnel ;  make  arrange- 
ments for  water,  construct  ditches,  flumes,  and  sluices, 
and  finally  the  incidental  charges  arising  at  all  mining 
operations,  —  are  items  that  the  gold  from  the  mine  must 
more  than  pay. 

There  have  been  a  few  cases  where  drifting  in  ancient 
river  beds  could  be  carried  on  without  driving  a  tunnel. 
Such  mines  are  located  in  places  where  the  modern 
rivers  have  cut  across  the  ancient  rivers  instead  of  run- 
ning parallel  with  them. 

Shafts  and  inclines  on  bed  rock  have  been  put  down 
to  work  ancient  rivers,  but  are  not  as  cheaply  worked  as 
tunnels,  since  a  hoisting  plant  is  required  to  raise  the 
material  to  the  sluices  at  the  surface,  and  further,  pumps 
must  be  used  to  keep  the  mines  drained. 


240  EXPLOITING  PLACERS 

In  sinking  to  bed  rock  through  such  deposits  every 
foot  of  ground  won  must  be  timbered,  as  the  sides  of 
the  shaft  will  not  stand  unless  supported.  Often  quick- 
sand or  running  ground  is  encountered,  and  this  being 
difficult  to  penetrate,  it  may  necessitate  the  abandonment 
of  the  shaft.  Inclined  shafts  are  generally  sunk  so  as  to 
follow  the  rim  rock,  since  in  this  position  there  is  a  firm 
foundation  for  the  sills  of  the  timber  sets.  Should  an 
incline  be  put  down  in  the  gravel  bed,  the  timbers  would 
soon  be  moved  out  of  alignment  and  the  shaft  ruined. 

In  the  Atlin,  B.  C.,  district,  shafts  are  sunk  about 
90  feet  to  bed  rock,  through  material  that  contains  no 
stone  capping. 

The  bed  rock  has  a  slope  of  from  5  to  7  per  cent. 
From  the  shaft  drifts,  approximately  100  feet  wide  and 
450  feet  long,  are  driven.  The  shaft  is  timbered  from 
top  to  bottom  and  is  operated  by  a  steam  hoister.  The 
heaviest  timbers  procurable  are  used  for  posts  and 
caps  in  the  drifts  and  levels.  Within  a  year  15,000 
cubic  yards  of  pay  dirt  were  hoisted.  The  excavation 
made  required  2600  sets  of  timber  and  over  25,000 
lagging.  The  total  cost  of  wood  for  timber  and  fuel  at 
this  mine  was  about  $10,000,  but  as  the  gravel  ran  $4 
to  the  cubic  yard  a  snug  profit  was  made,  even  against 
such  odds  as  a  creek  running  into  the  mine,  owing  to  a 
cave  and  continuous  pumping.  The  mine  dirt  at  this 
place  is  loaded  into  cars,  raised  to  the  surface,  and  sent 
to  the  sluices  in  the  same  car  over  a  short  surface  track. 

This  is  but  one  illustration  of  drifting  in  that  district, 
under  a  blue  clay  over  which  runs  a  creek. 

In  some  cases  where  the  placer  deposit  and  the  mate- 


DRIFT   MINING  241 

rial  above  it  were  thick  and  conditions  would  permit, 
a  tunnel  has  been  driven  through  a  side  hill  to  act  as 
a  sluice  and  carry  the  debris  to  a  suitable  dumping 
ground.  The  valley  into  which  the  tunnel  empties 
must  be  lower  than  the  one  containing  the  deposit. 
After  a  tunnel  has  been  driven  a  shaft  is  sunk  in  the 
deposit  to  meet  it.  Down  this  shaft  the  surface  dirt 
is  washed  and  flushed  through  the  tunnel.  When 
bed  rock  is  reached  by  washing  away  the  dirt  from 
about  the  shaft,  a  rock  sluice  is  constructed  from  the 
bank  to  the  tunnel  and  regular  hydraulicking  carried 
on.  Sluice  boxes  and  riffles  are  constructed  in  the 
tunnel  whenever  the  bed  rock  is  so  soft  as  to  wear 
rapidly.  Bed-rock  sluices  may  be  constructed  in  hard 
rock,  but  since  they  cannot  be  cleaned  up  so  readily 
or  so  often,  wooden  sluice  boxes  are  preferred. 

Blasting  Gravel  Banks.  —  Hard  cemented  gravel  is 
not  readily  broken  from  a  bank  by  water  pressure,  and 
as  an  aid  to  the  water  powder  is  used  to  shatter  the 
ground.  For  this  purpose  it  is  necessary  to  drive  a 
level  in  the  bank  and  then  cross  levels  at  right  angles 
to  the  ends  of  the  level.  The  position  of  the  level  rela- 
tive to  the  height  of  the  bank  is  of  some  importance,  as 
well  as  the  stratum  of  dirt  in  which  the  level  is  driven. 
It  is  not  advisable  to  drive  on  bed  rock,  as  a  certain  part 
of  the  blow  resulting  from  a  blast  must  be  delivered 
downwards,  and  on  bed  rock  it  performs  no  useful 
work.  It  is  better  to  drive  the  tunnel  in  the  cemented 
gravel  than  in  a  stratum  above  or  below  it,  as  the  mate- 
rial is  very  difficult  to  shatter.  The  practice  in  Cali- 
fornia is  to  drive  the  level  at  two-thirds  the  height  of 


242  EXPLOITING  PLACERS 

the  bank,  for  instance,  a  bank  120  feet  high  would  have 
the  level  driven  at  a  height  of  80  feet  from  bed  rock. 

The  object  of  blasting  gravel  banks  is  to  shake  the 
material,  and  loosen  it  for  the  giants  to  wash  down. 
Nothing  would  be  gained  by  using  so  much  powder  that 
the  earth  would  be  thrown  out  like  rock  in  rock  blasts, 
from  the  fact  that  the  giants  cannot  wash  broken-down 
material  to  the  sluices  as  advantageously  as  when  the 
material  is  in  the  bank. 

The  kind  of  explosive  to  be  used  in  such  blasting 
operations  is  a  matter  of  convenience  rather  than 
choice,  although  in  most  cases  black  powder  is  the 
better.  There  is  an  exception  to  the  above  statement, 
namely,  where  water  is  the  tamping,  and  then  dynamite 
should  be  used. 

Dynamite  containing  from  40  to  50  per  cent  nitro- 
glycerine is  preferable  to  higher  grade  explosives,  as 
they  furnish  a  rending  rather  than  a  shattering  blow, 
approaching  somewhat  in  execution  the  blow  produced 
by  black  powder.  .'..;.;, 

Experience  must  be  the  guide  in  the  quantity  .of 
powder  to  use  in  bank  blasting,  for  instance,  some  banks 
require  i  pound  of  powder  for  each  50  cubic  yards  of 
gravel,  while  other  banks  require  i  pound  of  powder 
for  each  20  cubic  feet  of  gravel.  In  a  new  bank  it 
would  be  well,  therefore,  to  take  an  average  between 
these  two  extremes,  or  i  pound  of  powder  for  every 
35  cubic  yards  of  dirt  to  be  shaken.  If  this  quantity 
can  be  reduced  it  should  be,  but  if  it  does  not  accom- 
plish its  work  properly,  it  must  be  raised.  •..'*  . 

The  quantity  of  powder  required  for  a  blast  is  calcu- 


BLASTING   GRAVEL  BANKS  243 

lated  according  to  the  yardage  affected,  for  example: 
What  charge  of  powder  is  required  to  shake  a  bank 
50  feet  high,  the  main  drift  to  be  75  feet  long  and  the 
two  cross  drifts  30  feet  long  each  way,  and  at  right 
angles  to  the  main  drift?  The  number  of  cubic  yards 
shaken  will  be  about  the  dimensions  furnished  by  the 
solid  defined  by  the  data  in  the  example: 
Thus 


_  8333  cubic  yards> 


and     -2«?  =  238    pounds    of    powder  as    the  charge. 

O  J 

The  length  of  the  main  drift  heading  should  be  longer 
than  the  bank  is  high,  thus  making  the  distance  to  the 
surface  the  line  of  least  resistance  to  the  blast.  The 
charge  should  be  placed  about  half  and  half  in  each  end 
of  the  cross  drift  and  walled  in.  The  tamping  must  be 
done  carefully  and  carried  to  the  main  drift,  and  at 
this  point  a  wall  should  be  built  and  more  tamping 
added.  In  case  the  explosive  gases  are  given  space  to 
expand,  they  will  not  be  as  effective  as  when  they  make 
their  own  space  for  expansion,  for  which  reason  ram- 
ming the  tamping  is  not  objectionable.  Wherever 
possible  the  charge  should  be  fired  by  an  electric  bat- 
tery and  not  by  fuse.  In  case  the  explosive  is  black 
powder,  then  a  piece  of  dynamite  with  a  fulminate  cap 
inserted  should  be  used  as  a  detonator  instead  of  relying 
on  the  fuse  to  fire  the  powder. 

Fuse  is  an  uncertain  quantity,  for  it  is  apt  to  be 
cracked  in  unwinding  and  jamming;  again,  there  is  no 
certainty  of  the  charges  at  each  end  of  the  cross  drift 


244  EXPLOITING  PLACERS 

being  discharged  at  the  same  time;  and  further,  it  will  be 
liable  to  injury  during  tamping  operations.  If  it  must 
be  employed,  then  double  or  triple  tape  fuse  is  laid  in 
duplicate  lines  in  order  to  make  sure  of  a  successful 
blast.  Small  blasts  are  less  economical  than  large  ones; 
however,  a  series  of  small  blasts  are  more  effective  than 
one  large  one.  It  will  be  policy,  therefore,  in  case  the 
face  of  the  bank  will  permit,  to  drive  two  or  three  drifts 
about  75  feet  apart  and  make  the  cross  drifts  at  their 
ends  25  feet  long  each  way.  Each  cross  drift  should  be 
loaded  the  same  and  the  entire  series  fired  at  once. 

In  some  cases  there  is  one  drift,  and  from  this  two  or 
three  pairs  of  drifts  are  driven  at  right  angles.  The 
powder  must  be  now  proportioned  to  the  yardage 
each  charge  is  to  break.  The  charges  must  be  properly 
tamped  and  all  fired  at  once.  Judgment  must  be  used 
in  dealing  with  this  kind  of  blasting  if  the  maximum 
work  is  to  be  obtained  with  a  minimum  expenditure  of 
powder.  Experiment  and  close  observation  of  the  work 
accomplished  will  prove  more  satisfactory  than  any 
definite  rules  that  may  be  laid  down  for  the  use  of  powder. 

Mining  in  Alaska.  —  In  Alaska  the  summer  season  is 
too  short  to  thaw  the  ground  to  any  great  depth;  further, 
in  such  cold  climates  the  surface  is  usually  covered  with 
moss  that  prevents  the  sun's  rays  from  penetrating  the 
earth.  When  the  placer  gravel  is  not  over  12  feet 
thick  the  moss  and  all  other  vegetation  is  stripped  from 
surface  and  under  such  conditions  the  sun  will  thaw 
the  ground  from  i  to  2  feet  per  day. 

The  muck  does  not  thaw  as  fast  as  the  gravel.  How- 
ever, as  fast  as  a  layer  of  dirt  thaws  it  is  removed  by 


MINING  FROZEN  GROUND  245 

ground  sluicing,  until  the  pay  streak  is  reached.  The 
pay  streak  is  washed  in  sluice  boxes. 

Where  the  placer  ground  is  more  than  12  feet  deep, 
shafts  are  sunk  to  bed  rock.  The  top  or  muck 
soil  is  picked  and  shoveled,  but  when  gravel  is  reached 
it  is  either  thawed  by  wood  fires  or  by  steam  points. 
A  wood  fire  in  a  shaft  will  thaw  from  8  inches  to  i  foot 
per  day,  provided  there  is  not  too  much  frozen  water  in 
the  gravel.  When  bed  rock  is  reached,  drifting  is 
commenced,  and  either  wood  fires  or  steam  used  for 
thawing.  A  good  wood  fire  will  thaw  from  12  to  18 
inches  into  the  face,  and  a  fire  30  feet  long  doing  this 
amount  of  thawing  is  good  work  for  two  men  on  a  4- 
foot  pay  streak. 

Steam  is  now  more  generally  used  in  Alaska  than 
wood  for  thawing,  although  the  cost  of  coal  is  $25  per 
ton,  on  the  Seward  Peninsula.  The  plant  consists  of 
a  boiler,  connected  with  steam  pipes  leading  to  the 
face.  At  this  point  a  manifold  is  used,  to  which  several 
steam  hose  are  fastened.  To  the  free  end  of  each  hose 
a  nozzle  is  attached,  called  a  "  point."  The  point  is 
from  5  to  6  feet  long,  about  ij  inches  in  diameter,  with 
jet  holes  A  inch  in  diameter  at  the  pointed  end,  and 
a  drive  end  at  the  other.  The  hose  is  attached  to  a  tee 
near  the  drive  head.  The  points  are  placed  about  3 
feet  apart  in  a  breast,  and  are  gradually  driven  in  as  the 
steam  thaws  the  ground.  They  are  allowed  to  stand 
5  or  6  hours  under  a  steam  pressure  of  20  or  30  pounds 
per  square  inch,  when  they  are  disconnected.  The 
ground  is  picked  down,  loaded  into  buckets,  hoisted  to 
the  surface,  and  dumped  on  a  pile  as  fast  as  it  is  thor- 


246  EXPLOITING  PLACERS 

oughly  thawed.  As  soon  as  the  spring  thaws  com- 
mence, the  pile  is  sluiced  in  boxes.  Scrapers  attached 
to  horses  are  used  to  carry  dirt  from  the  pile  to  the 
head  of  the  sluice,  and  on  account  of  the  flat  ground 
scrapers  are  also  used  for  spreading  the  tailings.  As 
a  rule,  very  little  timbering  is  required  in  frozen  gravel ; 
in  fact,  it  is  safer  than  solid  rock.  It  is  customary  to 
drive  rooms  400  feet  long  and  from  30  to  70  feet 
wide  without  any  timber  to  support  the  roof.  In  the 
tundra  mines  on  Little  Creek  the  gravel  is  frozen  to  bed 
rock  which  is  at  a  depth  of  120  feet. 

Gold  was  discovered  in  Georgia  in  1828,  also  the  first 
accounts  of  the  use  of  the  rocker  in  America  are  credited 
to  Dahlonega,  Georgia.  While  the  Californians  de- 
veloped hydraulic  mining,  we  are  informed  by  Claude 
Hafer1  that  nozzles  and  ditches  were  used  in  Georgia  so 
early  as  1868.  This  does  not  precede  the  rawhide  hose 
of  Mattison,  although  it  shows  that  at  this  time  hydrau- 
licking  was  firmly  established.  The  system  adopted  in 
Georgia  consists  in  cutting  into  the  hillside  along  the 
strike  of  the  mineral  deposit  with  a  giant,  after  which 
the  broken  down  material  is  swept  by  the  current  into  a 
flume  through  which  it  passes  to  a  mill  generally  located 
on  a  stream  bank  and  operated  by  water  power.  The 
bottom  of  the  flume  is  fitted  with  racks  that  act  as  riffles 
and  collect  the  coarse  gold.  At  the  mill  the  fine  sand  and 
mud  are  run  to  waste,  the  coarse  rock  is  broken  with 
stamps  and  the  gold  recovered  as  far  as  possible  by  amal- 
gamation. By  this  means  the  low-grade  saprolite  ores 
have  been  cheaply  treated  which  without  the  aid  of  the 

1  (Mining  World,  Vol.  XLV,  No.  14,  p.  611.) 


MINING  FROZEN  GROUND  247 

giant  could  not  have  been  profitably  worked.  The 
giants  operate  under  a  head  of  from  100  to  200  feet  and 
are  connected  by  pipes  with  ditches  along  the  ridges 
above.  In  order  to  reach  elevation  and  so  obtain  head 
the  ditches  are  many  miles  in  length  as  they  follow  the 
surface  contours. 

At  the  present  writing  there  being  more  returns  by 
converting  the  ditch  water  into  hydro-electric  power  not 
much  is  now  used  for  gold  mining.  On  one  ditch  line 
which  was  42  miles  long,  tunnels  were  driven,  and  an 
inverted  siphon  used  to  carry  the  water,  features  which 
show  that  the  California  method  was  closely  followed. 

In  the  southern  states  of  South  Carolina,  Florida  and 
to  a  less  extent  in  Tennessee,  the  giant  is  used  for  strip- 
ping the  surface  above  phosphate  deposits,  and  then  for 
sluicing  the  phosphate  rock  carrying  material  to  sumps 
from  which  it  is  pumped  to  washers  for  further  concen- 
tration. The  power  or  pressure  for  the  giants  is  obtained 
from  centrifugal  pumps,  also  the  movement  of  the  ma- 
terial from  the  sump  to  the  washer  is  accomplished  by 
similar  pumps. 

Two  articles,  one  by  E.  H.  Sellards,  State  Geologist  of 
Florida,  and  one  by  James  A.  Barr  will  be  found  in  "the 
Transactions  of  the  American  Institute  of  Mining  Engi- 
neers for  1914,  that  deal  with  hydraulicking  of  phosphate 
deposits. 

The  value  of  the  giant  for  stripping  ground  from 
mineral  deposits  under  some  conditions  is  now  fully 
established  and  found  to  be  the  most  economical  method 
where  water  and  fall  are  to  be  obtained. 

To  return  to  the  subject  of  drift  mining  it  is  to  be 


248  EXPLOITING   PLACES 

understood  that  it  is  comparatively  slow  work  and  there- 
fore expensive  because  the  broken  material  must  be 
carried  from  the  mine  and  washed  outside. 

Recently  in  the  Magalia  District  in  California,  where 
drift  mining  was  once  extensively  practiced,  the  plan 
which  is  believed  to  be  experimental  is  as  follows :  Water 
is  piped  to  the  face  in  the  Mineral  Slide  mine,  where  it  is 
spurted  against  the  ground  and  allowed  to  flow  through 
the  drift  to  daylight  in  sluice  boxes.  Previous  to  this 
it  was  the  custom  to  tram  the  dirt  to  a  hopper  and  wash 
it  from  the  hopper  at  the  mouth  of  the  drift  into  sluice 
boxes. 

Butte  County,  California,  in  the  vicinity  mentioned, 
has  had  several  drift  mines  in  operation  for  many  years, 
but  most  of  the  work  is  done  on  the  order  of  pocket 
mining,  as  in  this  vicinity  the  richest  drift  in  California 
has  been  found.  The  Magalia  mine  is  said  to  have 
carried  gold  that  panned  from  $80  to  $100  per  shovel  in 
one  part  of  the  channel.  The  Emma  Mine  also  was 
noted  for  its  richness. 

Undoubtedly  there  will  be  considerably  more  gold 
recovered  from  this  district  when  engineers  turn  their 
attention  to  some  better  method  of  recovery  than  is  now 
being  practiced. 


CHAPTER  IX. 

EXPLOITING    PLACERS.  —  (Continued.) 

Mining  in  North  Carolina.  —  There  is  a  belt  of  chlor- 
itic  schists  extending  from  Georgia  to  Nova  Scotia  in  a 
northeasterly  direction.  The  schists,  which  are  meta- 
morphosed and  impregnated  with  quartz  stringers,  have 
been  assigned  by  geologists  to  Cambrio- Silurian  times. 
The  quartz  in  these  schists  is  highly  mineralized  in  places, 
and  carries  gold,  silver,  copper,  lead,  arsenic,  antimony, 
and  possibly  other  metals.  In  some  localities  this  belt 
of  rocks  has  been  altered,  particularly  in  North  Caro- 
lina; while  in  other  localities  it  is  evidently  unaltered, 
particularly  in  New  England.  Owing  to  the  physical 
condition  of  these  rocks  in  North  Carolina  they  are 
in  several  localities  termed  placers,  and  are  worked  as 
such;  but  in  order  to  work  them  profitably,  methods 
that  are  economical  and  efficient  must  be  adopted. 
While  the  placers  are  considerably  richer  than  the 
majority  of  western  placers,  nevertheless  they  are  not 
as  readily  worked. 

The  gold  is  in  a  fine  condition,  but  that  is  not  the 
entire  reason  why  it  cannot  be  recovered  by  methods 
that  have  proved  efficient  in  the  West.  Experience  has 
convinced  most  miners  that  hydraulicking  is  not  suited 
to  these  deposits,  owing  to  the  clay  and  the  impurities 
which  they  carry  and  the  fineness  of  the  gold. 

249 


250  EXPLOITING  PLACERS 

The  placers  which  cover  wide  areas  in  North  Caro- 
lina have  been  a  source  of  aggravation  to  miners,  whe 
have  seen  others  that  carry  very  much  less  gold  worked 
at  a  profit. 

To  the  uninitiated  it  would  seem  that  it  was  merely 
necessary  to  turn  on  the  water  in  order  to  become  wealthy. 

At  the  Edith  mine  in  Catawba  County  nearly  every 
phase  of  hydraulicking  known  has  been  practiced  with 
indifferent  success.  Owing  to  a  scarcity  of  surface 
water  it  was  necessary,  in  order  to  mine  and  sluice  the 
ground,  to  sink  shafts;  construct  a  large  retaining  dam, 
to  form  a  settling  pond;  and  finally  pump  the  water 
from  the  settling  pond  back  to  the  mine.  To  sluice 
the  dirt  to  the  settling  pond  it  was  necessary  to  drive  a 
tunnel  and  dig  ditches.  In  addition  to  this  work,  con- 
siderable money  was  expended  for  boilers,  pumps,  and 
water  pipes. 

While  there  was  not  sufficient  gold  recovered  by 
hydraulicking  to  pay  expenses,  still  there  was  enough 
to  entice  the  owner  to  renewed  experiments  with  the 
hope  of  final  success. 

The  author  believes  he  was  the  first  to  suggest  the 
use  of  the  log  washer  for  such  deposits,  basing  his  belief 
on  its  fitness  from  a  knowledge  of  the  good  work  accom- 
plished in  washing  phosphate  rock,  iron  and  zinc  ores. 
Mr.  Overton  was  the  first  to  put  the  idea  into  practice, 
and  originated  the  washer  shown  in  Fig.  71. 

The  washer  is  in  two  units,  each  having  a  single  log, 
driven  by  belts  from  the  same  line  shaft.  Each  log  is 
8  inches  in  diameter,  constructed  of  steel  pipe,  rein- 
forced by  wood  inside  to  add  stiffness.  The  paddles 


LOG  WASHERS 


251 


are  arranged  spirally  as  on  any  log  washer,  but  differ 
from  those  usually  adopted,  being  flattened  cast-iron 
blocks  weighing  9  pounds  each. 

The  logs  are  geared  to  run  at  300  revolutions  per 
minute,  at  which  speed  the  blocks  act  as  hammers  and 
break  the  material.  (At  the  Catawba  mine  the  speed 
is  but  90  revolutions  per  minute.)  The  blocks  are  not 
intended  to  break  hard  rock,  but  medium  hard  rock. 
The  troughs  in  which  the  logs  revolve  are  semicircular, 


FIG.  71. 

made  of  J-inch  boiler  plate  and  supplied  with  a  wooden 
top  that  locks  to  the  trough.  The  first  washer  is  18 
feet  long,  the  second  12  feet  long,  each  being  given  a 
rise  to  the  discharge  end  of  about  J  inch  per  foot,  the 
object  being  to  form  a  larger  receptacle  at  the  entrance 
than  at  the  discharge  end  of  the  trough.  At  the  dis- 
charge end  of  each  washer  is  a  spout,  b,  leading  to  a 
rotary  screen  2X4  feet;  the  first  screen  having  f-inch 
openings,  and  the  second  one  J-inch  openings.  Below  each 
screen  is  a  trough.  The  first  trough  discharges  the 


252  EXPLOITING  PLACERS 

material  that  goes  through  the  meshes  of  the  first  screen 
into  the  second  washer,  while  the  second  trough  dis- 
charges the  material  to  the  riffles. 

The  material  to  be  washed  is  delivered  through  the 
hopper  to  the  trough,  where  the  coarser  part  is  worked 
forward  by  the  spiral  arrangement  of  the  paddles  to  the 
spout,  leaving  the  gold  and  most  of  the  heavy  sand 
behind. 

All  material  leaving  the  first  box  flows  into  the  screen, 
which  removes  all  stones  larger  than  f-inch  diameter. 
The  remainder  falls  through  into  launder,  and  flows 
into  the  top  of  the  second  washer.  The  stones  that 
did  not  go  through  the  screen  mesh,  work  out  at  the 
end  and  fall  on  a  short  endless  belt  that  conveys  them  to 
a  long  endless  belt  moving  in  a  direction  parallel  to  the 
length  of  the  washer.  The  long  belt  conveys  the  stones 
coming  from  both  screens  to  the  tailing  sluice  shown  in 
Fig.  72.  Each  of  the  four  washers  at  this  mine  is  sup- 
plied with  riffles  75  feet  long  r,nd  about  4  feet  wide. 
The  riffles  are  seen  in  the  illustration  to  be  on  each  side 
of  the  conveyer  belt,  and  all  discharge  into  a  common 
tailing  sluice. 

The  riffle  floors  are  of  2 -inch  plank,  with  2-inch  diam- 
eter holes  about  i  inch  deep,  bored  in  them.  The  holes 
which  are  staggered,  are  charged  with  a  small  quantity 
of  mercury.  Very  little  gold  is  caught  in  the  riffles,  the 
greater  quantity  being  caught  in  the  washers  in  about 
the  following  percentages: 

First  washer,  80  per  cent  of  the  gold. 

Second  washer,  18  per  cent  of  the  gold. 

Riffles,  2  per  cent  of  the  gold. 


253 


254 


FIG.  73. 


LOG  WASHERS 


255 


Fig.  73  is  an  illustration  of  the  Edith  mine  under  the 
present  working  conditions,  with  a  dirt  bank  116  feet 
high.  The  log  shanty  in  the  excavation  is  the  pump 
house  of  the  main  water  supply,  and  is  located  over  a 
shaft.  From  the  bench  of  earth  on  which  the  pump 
house  stands,  drill-holes  are  put  down,  squibbed  with 
dynamite,  and  blasted  with  black  powder.  The  blast 
shakes  the  dirt  so  that  when  it  reaches  the  loaders 


FIG.  74. 

at  the  bottom   of  the  cut  it   is   in  condition   for  easy 
shoveling. 

Twelve  men  load  400  tons  daily  into  cars.  The  dirt 
is  hoisted  up  an  incline  and  dumped  automatically  into 
a  hopper,  that  is  flushed  by  a  stream  of  running  water. 
The  water  carries  the  dirt  to  grizzles  having  2j-inch 
spaces.  All  hard  rock  which  is  too  large  to  pass  through 
the  bars  is  thrown  out,  while  the  smaller  stuff  is  sluiced 
to  the  washers  through  the  sluice  box,  constructed  as 


256  EXPLOITING   PLACERS 

shown  in  the  plan,  Fig.  74.  There  are  4  washers  at  this 
mine,  each  capable  of  washing  100  tons  of  dirt  in  10 
hours  with  75  gallons  of  water  per  minute.  It  is,  there- 
fore, necessary  to  make  as  even  a  distribution  of  the 
material  as  possible,  and  this  is  accomplished  as 
shown. 

The  value  of  the  gold  recovered  is  60  cents  per  ton  of 
dirt.  The  clean-up  of  the  washers  takes  place  once  a 
week.  .  It  is  performed  by  shutting  down  the  mine  for 
half  a  day  and  running  clean  water  through  the  washers 
until  it  comes  out  clean  at  the  riffles.  The  top  is  taken 
from  the  washers,  and  the  material  in  them  is  shoveled 
into  buckets  and  dumped  in  the  clean-up  box.  There 
is  a  trough  leading  from  the  clean-up  box  supplied  with 
Hungarian  riffles  containing  mercury.  The  mercury  in 
this  trough  seems  to  catch  all  the  free  gold,  showing 
that  the  scrubbing  and  washing  made  it  susceptible  to 
amalgamation.  Figure  75  shows  the  washing  system 
before  it  was  housed  at  another  plant  in  North  Carolina. 

Steam  Shovel  Mining.  —  The  problem  presented  to 
the  Atlin  Consolidated  Mining  Company  was  the  excavat- 
ing, hoisting,  and  washing  of  a  20-foot  bank  of  compact 
yellow  gravel.  No  natural  dump  existed  for  the  storage 
of  a  large  mass  of  tailings,  and  stacking  and  sluicing  had 
to  be  resorted  to.  The  plant  shown  in  Fig.  76  consists 
of  a  steam  shovel,  a,  having  a  dipper  that  has  a  capacity 
of  if  cubic  yards;  18,  3-cubic-yard  capacity  side  discharge 
ore  cars  &,  having  a  3-foot  gauge,  to  run  on  a  30-pound 
rail  track;  an  inclined  plane,  c,  having  a  30°  slope,  and 
terminating  in  a  platform  45  feet  above  the  bed  rock. 
The  cars  dump  their  contents  on  the  platform  into  chutes 


STEAM  SHOVEL  MINING  257 

provided  with  grizzles  made  of  rails.  The  large  material 
shears  off  the  rails  and  falls  to  the  stone  dump;  the  small 
material  passes  through  the  bars  into  the  sluice.  The 
sluice  is  4  feet  each  way  and  144  feet  long,  set  on  a  grade 
of  10  per  cent.  The  first  48  feet  are  paved  with  45- 
pound  rails,  placed  longitudinally,  the  remainder  of  the 


FIG.  75. 

sluice  with  3  X  3  X  J-inch  angle  iron  forming  cross 
riffles.  The  tail  sluice  and  the  extensions  are  block 
paved  and  given  a  grade. 

The  arrangement  of  the  tail  sluices  is  similar  to  that 
shown  in  Fig.  50,  where  there  is  a  lack  of  dumping 
ground  and  Y's  are  constructed.  The  plant  is  worked 


258 


EXPLOITING   PLACERS 


by  electricity,  as  far  as  hoisting  and. haulage  are  concerned. 
The  shovel,  however,  is  operated  by  steam,  the  digging 
engine  having  100  horse-power,  while  the  thrust  and 
swinging  engines  are  30  horse- power  each. 

The  plant  successfully  handles  1500  cubic  yards  of 
gravel  per  day,  and  employs  from  30  to  40  men.     The 


FIG.  76. 


water  is  taken  from  Pine  Creek,  which  furnishes  about 
1500  miner's  inches  for  washing  purposes,  while  the  elec- 
tric power  is  purchased  from  a  nearby  power  plant.  No 
statistics  are  furnished  in  regard  to  the  value  of  the 
gravel  or  the  cost  of  working.  However,  the  Guggenheims 
are  interested  in  the  company,  which  is  a  sufficient 
guarantee  that  it  is  not  being  operated  at  a  loss. 

Cableway  with  Self-filling  Bucket.  —  In  the  Alder 
Gulch  of  historic  fame,  a  placer  deposit  was  once  worked. 
The  German  Bar  Mining  Company,  Virginia  City, 


CABLEWAY  MINING 


259 


Montana,  believed  it  was  worth  reworking,  provided  they 
could  excavate  at  low  cost  and  transport  the  material 
to  a  tower  of  sufficient  height  to  furnish  a  sluice  and  a 


FIG.  77. 

dump  ground.     The  Lidgerwood  Manufacturing  Com- 
pany furnished  the  plant  for  them,  which  consisted  of 


260  EXPLOITING  PLACERS 

power  to  run  a  radial  traveling  cableway,  a  pivoted 
tower  and  hopper,  and  a  self- filling  bucket. 

The  pivot  tower,  Fig.  77,  had  a  large  hopper,  a,  40 
feet  above  the  ground,  into  which  the  bucket,  b,  dis- 
charged gravel  to  a  30-inch  sluice,  c,  set  on  a  5  per  cent 
grade.  The  sluice,  which  was  200  feet  long,  discharged 
its  fine  tailings  25  feet  above  bed  rock,  and  its  coarse 
tailings  near  the  tower. 

The  pivot  tower  had  a  ball-bearing  top,  d,  arranged  to 
turn  on  its  axis,  and  so  allowed  a  second  traveling  head 
tower,  a,  Fig.  78,  to  move  through  an  arc  of  180°. 

The  latter  carried  the  boiler,  machinery,  tower,  and 
cable  anchorage,  and  traveled  on  curved  tracks.  The 
excavation  was  made  along  radial  lines,  and  thus  a 
semicircular  pit  was  worked  out  around  the  hopper 
tower.  After  each  semicircular  pit  was  excavated,  the 
entire  plant  was  moved  forward  and  another  pit  made. 

The  Knight  excavating  bucket  was  developed  to  dig 
tough  ground  by  shaving  the  top,  and  at  the  same  time 
crowding  right  into  the  material.  The  bucket  is  sup- 
plied with  teeth  that  strike  the  material  as  it  is  dropped 
by  the  fall  rope.  The  illustration,  Fig.  77,  shows  it,  how- 
ever, in  the  position  it  assumes  when  loaded. 

The  method  of  excavating  is  as  follows:  The  carriage, 
with  bucket  hanging  teeth  downward,  is  run  out  on  the 
cable,  and  the  bucket  dropped.  The  bucket  strikes  the 
ground  teeth  first,  settles  down  on  its  bottom,  and,  as 
carriage  continues  toward  the  traveling  tower  with  hoist- 
ing line  slack,  the  bail  falls  into  its  natural  position,  the- 
back  catch  automatically  locking  itself,  ready  for  digging. 
When  the  carriage  has  reached  a  position  much  nearer 


26l 


262  EXPLOITING  PLACERS 

the  tower  than  the  bucket,  the  con veying-drum  brake  is 
thrown  in,  the  carriage  held  stationary  on  the  cable  while 
the  hoisting  rope  is  tightened,  thus  giving  to  the  bucket 
a : long  inclined  draft,  which  enables  it  to  fill.  This  draft 
may  be  varied  by  simply  changing  the  position  o*  the 
carriage  with  respect  to  the  bucket. 

The  ease  in  changing  the  angle  of  draft  is  of  the  ut- 
most importance  in  adapting  the  bucket  to  the  material 
and  depth  of  cut. 

The  bucket  draws  into  the  material,  the  strain  increas- 
ing until  the  teeth  are  buried  in  the  ground,  when  the 
leverman  releases  the  conveying  brake,  allowing  the  car- 
riage to  gradually  slip  back  to  a  position  over  the  bucket, 
thus  gradually  changing  the  draft,  the  bucket  meanwhile 
continuing  to  dig  until  the  carriage  is  directly  over  it,  by 
which  time  it  is  filled.  It  is  then  hoisted  and  conveyed 
to  be  automatically  dumped  into  the  hopper. 

On  level  or  difficult  ground,  the  long  draft,  gradually 
decreasing,  is  absolutely  necessary,  and  it  can  only  be 
secured  with  the  endless-rope  system.  Even  in  high 
banks  the  changing  draft  is  of  great  value,  as  the  bucket 
may  be  hoisted  as  soon  as  filled  without  having  to  drag 
it  through  all  the  material  higher  up  the  slope.  The 
changes  are  made  without  stopping  the  engine,  or  motion 
of  bucket,  and  effect  a  decided  saving  in  time  of  filling. 

The  fine  gravel  dumped  in  the  hopper,  is  washed 
through  the  grizzly,  m,  into  the  sluice,  and  thus  separated 
from  the  large  stones.  The  water  comes  to  the  hopper 
through  a  1 2-inch  diameter  pipe,  n,  either  from  a  side 
hill,  ditch,  or  a  pump.  In  this  case  it  was  a  ditch  that 
furnished  a  pressure  of  40  pounds  per  square  inch. 


CABLEWAY  MINING  263 

The  bucket  had  a  capacity  of  i  J  cubic  yards,  and  400 
buckets  have  been  filled  in  10  hours.  As  soon  as  the 
bucket  made  a  channel  to  bed  rock,  it  was  used  as  a 
bed-rock  sluice  through  which  the  top  soil  and  fine 
material  were  washed.  The  water  rushing  through  the 
cut  towards  the  bucket  carried  the  lighter  material  to  a 
bed-rock  flume  having  a  grade  of  i  per  cent,  which  was 
not  sufficient  to  move  the  gold-bearing  gravel,  and  this 
was  excavated  by  the  bucket. 

The  grizzly  was  made  of  J  X  3j-inch  iron  bars  with 
2-inch  spaces  between  them. 

The  boulders  that  pass  over  the  grizzly  stack  up  on 
either  side  of  the  tower,  while  the  gravel  that  passes 
through  the  chute  falls  5  feet  to  the  sluice  shown  in  Fig. 
51.  The  sluice  bottom  is  covered  for  24  feet  with  16- 
pound  mine  rails,  the  flanges  being  placed  close  together. 
The  remainder  of  the  sluice  is  covered  with  blocks  4X4 
inches  and  separated  crosswise  by  strips  of  wood  2  inches 
high  to  form  the  riffles.  The  labor  force  for  this  cable- 
way  consists  of  5  men,  —  engineer,  fireman,  signal  man, 
hopper  man,  and  rigger.  There  are  many  placers  in  the 
South  where  cableways  could  be  used  to  advantage  to 
dig  and  transport  material  to  log  washers.  There  are 
other  places  in  the  West,  particularly  Nevada  and  Ariz- 
ona, where  they  could  also  be  used  to  advantage.  In 
fact,  the  system  of  cableways  has  been  developed  until 
its  flexibility  adapts  it  to  many  kinds  of  placer  mining. 


CHAPTER  X. 

GOLD  DREDGING. 

Dredging  has  come  into  prominence  within  the  last  15 
years.  New  Zealand  is  the  original  home  of  the  success- 
ful dredge,  where  it  has  been  operated  since  1886.  On 
the  Molyneux  River,  in  New  Zealand,  there  were  at  one 
time  sixty  dredges  in  operation,  and  the  evolution  of  the 
present  type  was  brought  about  by  the  experience  origi- 
nating in  that  country.  The  river  bars  gave  indications 
of  gold,  and  being  at  times  rich,  it  was  known  that  the 
river  bottom  must  contain  gold  in  paying  quantities. 
The  miners  of  the  earlier  days  could  work  the  shores  of 
the  river  with  spoons,  which  consisted  of  a  bag  laced  or 
riveted  around  an  iron  frame  and  secured  at  the  end  of  a 
long  pole,  so  adjusted  and  weighted  that  it  could  be  drawn 
along  the  bottom.  When  filled,  or  partly  so,  it  was 
hauled  up.  Boats  were  next  used  with  this  spoon,  and 
an  auxiliary  boat  contained  a  rocker  for  separating  the 
gold  from  the  dirt.  This  dredging  was  the  forerunner 
of  the  present  bucket  system  of  elevating. 

"The  first  primitive  vessel  took  the  form  of  a  couple 
of  barrels  surmounted  by  a  timber  platform,  on  which 
the  dirt  was  shovejed  by  a  man  standing  in  the  water, 
the  dirt  afterward  being  taken  on  shore  and  cradled." 
''The  next  dredge  consisted  of  three  canoes  lashed 
together  by  a  board  platform  and  secured  by  ropes  to 

264 


DREDGING  265 

the  shore  to  steady  it.  It  was  provided  with  the  spoon 
already  mentioned  for  excavating.  This  contrivance  was 
the  first  pontoon  dredge.  The  next  step  was  to  use 
water-power  to  work  the  spoon,  and  where  such  power 
was  not  available  dredging  was  carried  on  by  spoons 
being  raised  by  crab- winches  worked  by  hand." 

Mr.  Ward,  the  inventor  of  the  current  spoon-dredge, 
designed  and  worked  successfully,  in  1870,  a  bucket- 
and-ladder  dredge.  The  motive  power  for  moving  the 
buckets  he  obtained  from  current  wheels  in  the  river. 
This  was  followed  by  hand-power,  then  steam-power, 
and  electricity  as  practiced  at  the  present  time. 

Dredging  is  one  of  the  popular  ways  of  recovering  gold 
where  the  depth  of  the  alluvion  does  not  exceed  60  feet 
below  water  level  or  20  feet  above.  The  number  of 
dredges  at  work  10  years  ago  was  about  60;  at  the  pres- 
ent time  there  are  said  to  be  500  at  work  in  various 
parts  of  the  world.  The  ease  with  which  placer  ground 
can  be  prospected,  and  the  certainty  of  cost  and  recovery, 
place  dredging  on  a  commercial  basis  almost  if  not 
quite  as  secure  as  manufacturing. 

Success  or  failure  in  any  line  of  business  depends  upon 
experience  and  watchfulness. 

To  assume  that  any  one  kind  of  dredge  is  suitable 
for  every  kind  of  ground  is  a  mistake,  yet  this  is  done, 
and  failures  are  recorded. 

One  kind  of  dredge  is  better  adapted  to  one  kind 
of  ground  than  another.  For  instance,  where  the  gravel 
bed  contains  few  boulders  and  bed  rock  is  soft,  the 
bucket  dredge  finds  favor;  or  where  the  boulders  are 
Urge  and  the  ground  tough  and  cemented,  the  dipper 


266  GOLD  DREDGING 

dredge  is  to  be  preferred;  again,  where  the  material  is 
loose  sand,  as  in  some  river  beds,  the  suction  pump  is 
preferred. 

To  reduce  dredging  to  a  metallurgical  proposition 
some  system  of  sampling  tailings  to  ascertain  the  loss 
that  is  occurring  must  be  adopted.  Samples  for  this 
purpose  should  take  all  the  stream  part  of  the  time,  and 
the  sample  so  obtained  should  be  concentrated  in  a 
rocker,  and  the  gold  extracted  by  mercury. 

There  seems  to  be  a  great  diversity  of  opinion  in  regard 
to  the  proper  method  of  saving  gold  on  dredgers.  Some 
operators  prefer  the  sluice  box,  others  prefer  tables, 
and  still  others  a  combination  of  both.  The  latter 
method  is  probably  the  best,  since  no  arrangements  have 
yet  been  devised  that  will  save  all  the  gold ;  in  fact,  it  is 
good  work  to  save  70  per  cent.  Sluice  advocates  believe 
in  long  sluices,  although  J.  P.  Hutchins1  states  a  case 
where  material  that  passed  through  a  120-foot  sluice 
was  redredged  and  passed  through  a  30-foot  sluice,  with 
the  result  that  the  short  sluice  yielded  as  much  as  the 
long  sluice,  under  adverse  conditions.  There  has  been 
very  little  improvement  in  the  mechanism  or  construc- 
tion of  dredges,  although  the  cost  of  working  has  been 
somewhat  reduced  by  increasing  the  capacity.  Where 
two  or  more  dredges  are  working  near  each  other  a 
central  power  plant  will  considerably  reduce  the  cost 
of  the  process,  by  decreasing  the  cost  of  handling  fuel. 
No  attempts  have  been  made  to  save  the  black  sands, 
that  often  contain  values  which  run  from  one  to  ninety 
ounces  per  ton  of  sand,  and  that  sometimes  in  addition 

1  Mineral  Industry,  1905. 


DREDGE  IMPROVEMENTS  267 

carry  silver,  platinum  metals,  and  copper.  Sands  in 
the  Caribou  District,  British  Columbia,  carried  64  ounces 
of  platinum  per  ton  of  concentrates,  worth  $1920  at  the 
present  price  $30  per  ounce. 

It  is  well  known  that  heavy  gold  can  be  caught  in 
sluice  riffles,  except  when  it  is  coated  with  an  oxide  of 
other  material.  Basing  their  position  on  this  fact,  many 
dredge  operators  do  not  use  quicksilver  in  sluices,  con- 
sequently lose  fine  and  float  gold.  It  is  probably  for 
the  same  reason  that  gold-saving  tables  have  been  dis- 
carded for  sluices.  Australian  dredgers  and  Alaskan 
miners  do  not  use  quicksilver,  although  in  the  latter 
country  it  has  been  fully  demonstrated  that  quicksilver 
will  recover  considerable  gold  from  the  tailings.  If 
quicksilver  is  not  needed,  there  is  no  fine  gold  in  the 
placer,  a  condition  of  affairs  that  may  be  much  doubted. 

An  objectionable  feature  common  to  all  dredges,  par- 
ticularly bucket  dredges,  is  that  they  cannot  clean  the  bed 
rock  thoroughly.  Wherever  an  attempt  is  made  to 
clean  bed  rock  by  hand,  the  water  must  be  drained  off 
subsequently  to  carrying  the  tailings  beyond  a  point 
where  they  will  not  run  back  to  the  place  recently 
excavated.  It  is  probable  that  in  many  cases  a  suction 
pump  could  be  used  to  advantage  in  cleaning  bed  rock 
after  the  bucket  and  dipper  dredges  have  removed  the 
greater  part  of  the  gravel. 

The  principal  cause  for  the  recent  boom  in  dredging 
until  it  has  become  the  rival  of  hydraulicking  plants  in 
California,  is  that  the  returns  can  be  calculated  with 
much  certainty. 

The  difficulties  in  the  way  of  successful  recovery  by 


268 


GOLD  DREDGING 


dredging  are  yet  many,  not  in  the  commercial  sense  that 
dredging  will  not  pay  dividends,  but  in  the  metallurgical 
sense  of  saving  a  larger  percentage  of  the  gold.  It  has 
been  found  that  a  bucket  dredge  will  recover  70  per  cent 
of  the  values  shown  by  the  drill-holes,  and  that  the 
recovery  of  from  one  to  one  and  one-half  grains  of  gold 
to  the  ton  will  pay  expenses,  the  cost  of  operating  rang- 
ing from  3  cents  to  8.35  cents  per  cubic  yard.  The 
distribution  of  expenses  in  dredging  operations  are  about 
as  follows  per  cubic  yard: 


Hijh. 

Low. 

Cost  Working  5  Foot  Bucyrus  Dredge  Per 
Cubic  Yard.     Oroville. 

Pay  roll  .    . 
Power.    .    . 
Repairs  .     . 
Sundries.    . 
Taxes     .    . 

Total  .    .    . 

2.05 
1.77 
3-8o 
°-73 

I-I3 
1-34 
.61 

•52 

Lower. 
Repairs    . 
Labor  .    . 
Expenses  . 

i.  06  to  1.77  Average  1.415  cents 
2.  86  to  3.  03         "        2.945      " 
i.  64  to  2.  05         "        1.845       " 
0.64100.73         "        0.685 

8-35 

3.60 

Totals 

6.20  to  8.35        "       6.890          " 

The  cost  of  dredging  depends  upon  the  nature  of  the 
ground,  and,  other  things  being  equal,  the  capacity  of 
the  dredge;  since  fixed  charges  practically  remain  the 
same  whether  40,000  or  80,000  cubic  yards  of  dirt  are 
handled  monthly.  For  instance,  a  3j-foot  bucket  dredge 
mined  material  for  4.892  cents  per  cubic  yard,  while  a 
5-foot  bucket  dredge  mined  the  same  material  for  3.66 
cents  per  cubic  yard.  In  another  case  a  4-foot  bucket 
dredge  in  a  very  hard  compact  cement  gravel  could  not 
work  for  less  than  8.7  cents  per  cubic  yard. 

The  dredge  is  not  a  useful  arrangement  in  a  swift- 


COST  OF  DREDGING  269 

flowing  river,  and  is  best  suited  to  working  river  banks 
from  the  shore  inland,  in  some  cases  to  distances  over  a 
mile.  Dredges  working  inland  make  their  own  float/way 
as  a  usual  thing,  although  they  are  sometimes  greatly 
assisted  by  giants  or  steam  shovels  that  strip  the  top 
barren  dirt  above  water  level. 

The  construction  of  a  dredge  is  of  considerable  im- 
portance. For  instance,  in  a  practically  new  country 
where  no  dredging  has  been  done,  exceptional  care  should 
be  taken  to  investigate  the  kind  of  ground  the  dredge 
must  handle,  and  the  gold  it  is  to  save.  Small  dredges 
should  be  constructed  in  new  districts,  and  then,  if 
changes  are  necessary,  the  next  dredge,  which  will  be 
larger,  can  be  equipped  to  meet  the  demands. 

Dredges  cost  in  proportion  to  their  size  and  power. 
For  instance,  a  dredge  that  will  excavate  and  wash  40,000 
cubic  yards  of  dirt  per  month  would  cost  approximately 
$40,000,  while  a  dredge  capable  of  handling  60,000 
cubic  yards  of  dirt  per  month  would  cost  $60,000.  The 
increased  cost  is  due  to  the  enlarged  hull  and  heavier 
machinery  needed  to  handle  increased  quantities  of 
material  in  a  given  time.  The  above  cost  refers  to 
bucket  dredges.  Dipper  and  suction  dredges  will  cost 
less  than  bucket  dredges ;  and,  again,  the  suction  dredge 
will  cost  less  than  the  dipper  dredge,  in  fact,  a  first-class 
suction  dredge  can  be  constructed  for  $15,000. 

Mr,  R.  H.  Postelthwaite  claimed  in  1897  that  any 
ground  not  deeper  than  60  feet  below  water  level,  or 
not  more  than  20  feet  above,  and  which  did  not  contain 
rocks  heavier  than  i  ton,  could  be  handled  at  from  3 
to  5  cents  per  cubic  yard. 


270  GOLD  DREDGING 

Subsequent  practice  has  corroborated  his  statement, 
and  in  one  case  the  cost  has  been  as  low  as  2.36  cents 
per  cubic  yard. 

The  constituent  parts  of  a  dredge  are: 

(a)  The  hull,  upon  which  the  machinery  floats. 

(b)  The  excavator  for  digging  and  raising  the  material. 

(c)  The  washing  apparatus. 

(d)  The  sluices  and  gold-saving  devices. 

(e)  The  tailings  stacker. 

(/)  The  power  plant  for  driving  the  machinery. 

The  Bucket  Dredge.  —  (a)  The  hull  of  all  dredges 
must  be  substantially  constructed  and  designed  for  the 
weight  of  the  machinery  it  is  to  carry.  More  than  one 
dredge  has  sunk  because  it  was  not  properly  calked  or 
designed. 

The  construction  of  the  hull  is  not  a  difficult  matter 
and  is  carried  on  as  for  any  lighter  that  carries  its  load 
on  its  deck. 

The  hulls  are  of  wood  and  vary  from  30  to  40  feet  in 
width  and  from  60  to  120  feet  in  length.  The  depth 
of  the  hull  is  usually  from  6  to  9  feet,  and  when  com- 
pleted and  weighted  with  machinery  draws  from  4  to  6 
feet  of  water  according  to  the  size.  The  frame  of  the 
scow  is  blunt  pointed  as  in  Fig.  79  for  river  dredging; 
but  for  inland  dredging  it  may  be  constructed  square  at 
both  ends,  as  there  is  no  current  to  contend  with.  The 
bucket  dredge  has  a  well  built  in  the  bow  that  practi- 
cally divides  that  in  two  parts.  Fig.  80  is  an  elevation 
of  the  dredge  shown  in  Fig.  79.  Its  different  parts 
will  be  described  in  order  as  we  proceed. 

Fig.  8 1  is  the  dredge  Indiana,  built  by  the  Bucyrus 


THE  BUCKET  DREDGE 


271 


272 


GOLD  DREDGING 


FIG.  80. 


EXCAVATORS  FOR  DREDGES        273 

Company,  and  is  used  for  the  purpose  of  describing 
the  various  essential  details  that  enter  into  the  construc- 
tion. It  is  an  electrically  driven  dredge,  otherwise 
boiler  stacks  would  be  in  evidence  as  in  Fig.  80.  The 
gantry,  a,  is  constructed  of  heavy  timbers,  that  rise 
about  20  feet  above  the  main  deck.  Rolled  steel  bars, 
H-shaped,  are  sometimes  substituted  for  timbers  in 
gantries,  although  they  possess  no  particular  advantages 
over  suitable  timber  sticks.  The  bucket  ladder,  6,  is 
a  substantial  steel-trussed  arm,  that  extends  some  dis- 
tance ahead  of  the  dredge,  the  length  depending  upon 
the  depth  to  bed  rock.  It  is  pivoted  to  the  driving 
shaft  at  the  upper  end,  and  supported  by  a  bail,  c, 
which  is  suspended  by  wire  ropes  from  blocks  attached 
to  the  cross-tree  of  the  gantry.  The  ropes  are  connected 
with  power,  so  that  the  ladder  may  be  raised  or  lowered 
as  found  necessary  while  excavating.  At  each  end  of 
the  ladder  there  are  tumbler  wheels,  whose  object  is  to 
give  motion  to  the  buckets.  The  upper  tumbler  is 
keyed  to  the  shaft  which  carries  the  driving  wheel,  d. 
Rollers  are  placed  at  intervals  on  the  ladder,  in  order 
to  decrease  the  friction  of  loaded  buckets,  e,  as  they 
move  upwards  to  the  dump,  located  on  the  top  deck  of 
the  boat.  The  buckets  can  dig  in  deep  or  shallow  water, 
but  must  be  pitched  in  each  case  by  the  bucket  ladder. 
The  tumbler  under  water  is  rotated  by  the  bucket  chain, 
which  is  set  in  motion  by  the  upper  tumbler  revolving 
on  its  shaft. 

(b)  Excavators  for  Dredges.  — There  are  three  kinds 
of  excavators  for  dredges,  —  the  bucket,  dipper,  and 
suction  pump. 


274 


BUCKET  EXCAVATORS  275 

i.  The  bucket  excavator  not  only  digs  the  dirt,  but 
elevates  it  to  a  hopper  at  the  top  of  the  dredge.  The 
bow  end  of  the  hull,  as  previously  mentioned,  is  divided 
through  the  center  in  order  to  permit  the  bucket  ladder 
to  be  raised  and  lowered,  and  the  elevator  buckets  to 
travel.  This  kind  of  dredge  is  not  tipped  when  a  load 
is  lifted  from  the  river,  consequently  the  plant  is  evenly 
balanced,  even  though  the  heavy  machinery  is  placed 
near  the  stern.  This  type  originated  in  New  Zealand, 
and  very  little  if  anything  has  been  added  to  its  improve- 
ment since  it  was  introduced  in  this  country.  The 
movement  of  the  buckets  is  slow  and  uniform,  the  rate 
of  travel  being  from  1 8  to  20  buckets  per  minute.  The 
speed  should  be  regulated  to  deliver  the  material  in  a 
fairly  uniform  manner,  as  the  feeding  is  a  matter  of  con- 
siderable importance.  With  buckets  the  material  is 
brought  up  in  comparatively  small  masses,  that  permits 
of  it  being  properly  washed  without  overpowering  suit 
ably  designed  screens. 

Buckets  are  usually  made  of  steel  with  lips  reinforced 
by  manganese  steel  strips  varying  in  thickness  from  i 
to  1}  inches.  The  lips  are  the  weakest  part  of  the 
bucket  dredge,  and  if  they  were  not  reinforced  as  de- 
scribed the  entire  bucket  would  need  replacing  from 
time  to  time.  Considerable  wear  and  tear  occurs  when 
working  in  hard  clay  containing  boulders,  as  a  boulder 
in  such  material  is  not  easily  removed,  and  will  cut  and 
wear  the  bucket  lip  quickly,  and  often  so  dent  the  bucket 
even  when  reinforced  as  to  make  it  practically  useless 
for  cutting  a  bank.  To  obviate  this  difficulty  it  is  cus- 
tomary to  drill  holes  ahead  of  the  dredge  working  inland 


276  GOLD  DREDGING 

and  shake  the  ground  with  a  blast.  This  will  enable 
the  bucket  to  pick  up  the  boulder  or  move  it  one  side. 
Here  the  Keystone  driller  again  finds  employment,  in 
drilling  blast-holes  ahead  of  the  dredge. 

The  buckets  are  secured  to  chains  by  rivets,  and  are 
with  the  chains  made  so  strong  that  if  they  encounter 
an  obstruction  that  they  are  unable  to  move  or  to  glance 
from,  they  will  stop  the  machinery.  The  capacity  of 
the  buckets  is  from  3  to  13  cubic  feet;  the  most  usual 
sizes  being  3,  5,  and  yj  feet,  and  these  at  a  speed  of 
1 8  buckets  per  minute  will  theoretically  deliver  120,  200, 
and  300  cubic  yards  per  hour. 

Owing  to  the  imperfect  filling,  the  practical  delivery 
will  average  about  two  thirds  of  the  above  quantities. 
The  Bucyrus  buckets  are  considered  more  efficient  than 
Risdon  buckets,  where  there  are  no  boulders,  and  the 
Risdon  buckets  are  considered  to  be  better  where  there 
•are  many  boulders.  The  only  difference  between  the 
two  consists  in  their  hooking-up  and  chain  construction. 
The  Bucyrus  buckets  are  placed  close  together,  while 
the  Risdon  buckets  have  a  bare  chain  link  between  them. 
It  is  claimed  by  the  Bucyrus  people  "that  Robinson's 
patent  steel  chain  has  advantages  over  all  others,  inas- 
much as  the  chain  pins  are  protected  and  lubricated  so 
that  sand  cannot  cut  out  the  links  and  pins,  necessitating 
their  frequent  renewal." 

The  depth  to  which  the  buckets  may  work  is  limited 
by  the  power  of  the  engine  and  length  of  the  bucket 
ladder,  but  for  deep  dredging  the  boat  must  be  con- 
structed accordingly.  Probably  the  average  depth  below 
water  level  so  far  worked  by  these  machines  is  40  feet, 


DIPPER  EXCAVATORS  277 

although  many  have  been  constructed  to  dredge  60 
feet. 

The  buckets  deliver  their  contents  into  a  hopper,  so 
constructed  that  all  material  falls  into  it.  No  material 
should  be  allowed  to  return  directly  from  the  bucket 
into  the  water,  as  there  is  a  probability  of  its  containing 
gold.  A  stream  of  water  should  be  used  to  clean  the 
buckets  at  the  hopper  when  digging  in  clayey  or  sticky 
ground. 

The  advantages  of  the  bucket  excavator  are: 

It  delivers  the  material  to  the  hopper  in  a  compara- 
tively uniform  manner; 

It  can  dig  deeper  than  other  excavators  with  less 
expenditure  of  power; 

It  requires  but  one  hull,  and  all  machinery  can  be 
placed  on  that  hull. 

The  disadvantages  of  the  bucket  excavator  are: 

It  cannot  raise  boulders  out  of  the  way,  but  bangs 
against  them  to  the  detriment  of  the  buckets,  without 
raising  material,  thereby  requiring  that  the  barge  be 
moved ; 

The  buckets  are  only  partially  filled,  and  permit  some 
fine  material  to  run  back  to  bed  rock,  which  they  are 
unable  to  clean,  if  hard,  and  only  partially  to  clean  if  soft. 

2.  The  Dipper  Excavator.  —  The  dipper  was  first 
adopted  for  dredging  gold  in  this  country.  It  has  been 
systematically  decried,  although  in  some  ground  it  has 
no  equal. 

The  dipper  excavator,  up  to  a  certain  depth,  depend- 
ing upon  the  length  of  the  dipper  arm,  is  able  to  move 
and  remove  larger  boulders  than  the  other  excavators. 


.278  GOLD  DREDGING 

This  is  made  possible  by  the  fork  on  the  end  of  the 
dipper,  the  large  mouth  of  the  dipper,  and  the  concen- 
tration of  power.  These  advantages  become  more  evi- 
dent when  one  takes  into  consideration  that  they  obviate 
the  necessity  of  raising  and  lowering  the  bucket  ladder, 
backing  and  filling,  with  consequent  cessation  of  work 
during  that  time,  and  swinging  the  scow  in  position. 
Further,  it  is  possible  to  excavate  more  ground  in  a  given 
.time,  closer  to  bed  rock,  and  on  account  of  the  lateral 
swing  of  the  bucket  arm,  a  wider  space  without  change 
of  the  scow's  position. 

The  opponents  of  the  dipper  usually  advance  two 
arguments  against  its  use:  First,  that  the  dipper  door 
cannot  be  made  tight  without  great  expense  for  gaskets 
—  and  consequently  there  is  apt  to  be  a  loss  of  gold 
unless  they  be  used. 

To  obviate  this  loss  from  leakage,  gaskets  of  common 
rubber  hose  are  so  arranged  as  not  to  come  in  contact 
with  the  material  during  its  discharge  from  the  dipper. 
These  gaskets  wear  well,  are  not  expensive,  and  can  be 
replaced  in  ten  minutes'  time,  if  necessary,  but  they  are 
not  absolutely  water  tight. 

As  the  material  is  brought  up  in  masses,  with  little 
water  in  comparison  to  the  bulk  of  material  raised  by 
the  other  two  classes  of  excavators,  the  loss  of  gold 
from  seepage  through  the  door  under  any  circum- 
stances is  slight,  and  probably  not  more  than  occurs 
from  the  continual  stirring  up  and  sliding  back  of  the 
ground  where  buckets  do  the  excavating,  and  which 
must  necessarily  loosen  and  precipitate  some  gold. 

The  second  objection  to  the 'dipper  is  stated  to  be 


279 


280  GOLD  DREDGING 

the  agitation  caused  by  the  dipper's  attack  on  the  mate- 
rial. This  attack  is  no  more  vicious  than  that  of  a 
bucket  in  comparison  with  their  sizes,  the  water  in  the 
dipper  being  pushed  out  gradually  as  the  material 
enters;  this  objection  is  tenable  only  where  the  ground 
is  loose,  and  the  gold  is  free  and  very  fine;  however,  in 
such  instances  the  bucket  is  likewise  objectionable. 

The  specific  gravity  of  gold  is  such  that  particles  the 
size  of  pin  heads  are  not  easily  floated  in  swift-running 
water,  and  hence  the  approach  of  the  dipper  is  not  apt 
to  cause  the  gold  to  float  one  side. 

Mr.  P.  Wright  says  "that  in  the  Beechwood  district 
of  Australia  "  he  found  95  per  cent  of  the  gold  within 
three  feet  of  where  it  was  filled  into  the  sluice,  the  gold 
lying  on  a  smooth  board,  and  yet  a  powerful  current 
failed  to  move  it. 

Mr.  Alex.  J.  Bowie  says  that  80  per  cent  of  the  gold 
recovered  is  found  within  the  first  200  feet  of  the  sluice, 
and  quotes  an  instance  where  in  a  100  days'  run  which 
cleaned  up  $63,000,  85^  per  cent  was  caught  in  the  first 
150  feet. 

Careful  consideration  of  the  imaginary  difficulties 
attending  the  use  of  the  dipper  which  are  advanced  will 
probably  lead  to  its  later  adoption,  since  it  has  no  equal 
for  moderate  depths  and  wide  range  for  handling  material. 

A  seriously  objectionable  feature  of  the  dipper  is  the 
intermittent  manner  in  which  it  brings  gravel  to  the 
hopper;  at  times  it  delivers  a  full  dipper,  but  more  fre- 
quently a  less  quantity,  with  much  water.  It  is  difficult 
to  receive  material  in  this  way,  and  generally  the  dipper 
will  require  another  scow  to  treat  the  material,  otherwise 


DIPPER  EXCAVATORS  281 

the  hopper  and  sluices  must  be  placed  upon  the  river 
bank. 

The  same  objections  apply  to  the  clam-shell  bucket 
in  a  greater  degree,  for,  should  a  stone  prevent  the  shells 
from  closing  tight,  the  gold  would  be  lost  in  getting  the 
material  to  the  hopper;  besides,  the  agitation  consequent 
upon  the  shutting  and  lowering  of  the  dipper  may  be 
sufficient  to  float  gold  away  from  the  material  being 
excavated.  These  excavators  work  very  satisfactorily  in 
dry  placer  ground. 

The  dredge  shown  in  Fig.  82  was  one  of  the  first 
constructed  in  this  country,  and  is,  or  at  least  was 
two  years  ago,  in  active  operation  on  the  Chestatee  River, 
Georgia. 

It  will  be  noticed  that  the  dipper  is  mounted  on  one 
barge  and  the  sluice  on  another.  This  on  first  thought 
is  objectionable,  but  on  reflection  there  does  not  appear 
much  doubt  but  that  a  barge  constructed  particularly 
for  cleaning  the  gold  furnishes  a  better  opportunity  and 
more  space  for  gold-saving  opportunities.  Some  dredges 
are  constructed  so  that  the  bucket  arm  can  be  brought 
back  to  dump  in  a  bow  hopper  placed  in  the  center  line 
of  the  barge  but  extending  over  the  bow;  others  have 
hoppers  constructed  on  the  sides  near  the  bow.  In  case 
that  the  hoppers  are  in  the  center  line  of  the  boat,  spuds 
must  be  used  in  the  rear;  but  where  the  hoppers  are 
placed  to  one  side  or  on  a  separate  barge,  spuds  must 
be  used  at  the  rear  and  on  the  dumping  side.  Several 
dredges  of  the  dipper  type  are  working  successfully  on 
the  Chestatee  River,  and  the  dippers  for  such  dredges 
vary  in  capacity  from  i  to  2j  cubic  yards.  The  dredge 


282  GOLD  DREDGING 

illustrated  washes  the  material  through  a  grizzly  by  a 
stream  of  water  into  a  sluice  box,  that  discharges  the 
tailings  in  the  river.  This  dredge  has  considerable  black 
sand  to  contend  with.  The  dipper  dredges  at  work  at 
Oroville,  California,  use  tailing  stackers,  and  pumps  for 
disposing  of  the  tailings.  They  also  use  screens  for 
disintegrating  and  washing  the  dirt.  According  to  the 
Marion  Steam  Shovel  Company,  the  two  dredges  in 
Oroville  are  among  the  most  successful  in  that  field 
to-day,  although  there  are  many  bucket  dredges  there 
for  comparison. 

3.  Suction  Dredges.  A  centrifugal  pump  with  a  12- 
inch  suction  hose  that  reaches  to  the  bottom  of  the  river, 
comprises  the  excavating  arrangement  on  what  are 
termed  suction  dredges.  The  hose  is  attached  to  a 
moving  crane  on  the  barge  so  that  it  can  be  moved  as 
desired. 

Mechanical  devices  and  water  jets  have  been  proposed 
to  loosen  the  material  at  the  suction  end.  These,  however, 
are  not  required  ordinarily,  as  the  pump  will  raise  sand, 
gravel,  and  even  rocks  approximately  the  diameter  of  the 
hose  in  size. 

The  most  successful  dredging  plant  of  this  kind  was 
that  of  Sweetser  and  Burroughs  on  the  Snake  River  near 
Minedoka,  Idaho.  This  plant  consisted  of  a  1 5-inch 
centrifugal  pump,  directly  connected  to  an  1 8-inch  tur- 
bine water  wheel.  The  gravel  and  water  together  were 
elevated  a  height  of  25  feet,  the  suction  being  20  feet, 
and  the  delivery  pipe  5  feet.  The  material  handled 
ranged  from  fine  sand  to  8-inch  boulders.  While  the 
suction  and  discharge  pipes  did  not  wear  rapidly,  the 


CENTRIFUGAL  PUMPS  283 

pump  propeller  and  casing  could  not  be  kept  long  in 
repair,  and  this  necessitated  frequent  stoppages,  until  a 
steel  lining  and  a  closed  impeller  were  introduced.  Even 
with  these  improvements  the  results  were  not  entirely 
satisfactory.  In  dredging  on  the  float  coal  in  the  Sus- 
quehanna  River  near  Nanticoke,  Pennsylvania,  there 
was  very  little  wear  on  the  pump  impeller  and  casing ;  in 
fact,  there  was  nothing  in  the  way  of  repairs  done  to  the 
pump  in  two  seasons,  although  it  handled  large  quanti- 
ties of  sand,  coal,  and  rounded  stones. 

While  the  system  is  cheap  as  regards  first  cost,  and 
takes  up  but  little  deck-room,  it  is  very  difficult  to  regu- 
late. At  one  time  the  pump  will  be  choked;  at  another 
time  nothing  but  water  will  be  delivered;  furthermore,  a 
natural  selection  of  sizes  takes  place.  At  one  time  there 
will  be  a  free  flow,  but  the  larger  material  that  moves 
slowly  will  gradually  form  a  layer  that  stops  all  flow. 
To  keep  the  Susquehanna  dredge  up  to  its  work,  it 
required  one  man  with  a  long  pole  to  keep  the  material 
stirred  up,  and  to  move  the  tail  pipe  from  the  hole  it 
quickly  dug  to  a  new  position  where  the  material  was 
within  the  suction  radius.  The  cost  of  working  gravel 
on  the  Minedoka  dredge  was  2  cents  per  cubic  yard. 
Its  success  was  due  to  gravel  being  washed  to  the  pump, 
to  its  working  where  the  tail  pipe  was  practically  always 
in  sight,  and  to  its  being  run  by  water-power.  The 
quantity  of  water  pumped  is  always  in  excess  of  the 
material,  and  the  power  consumed  is  out  of  proportion 
to  the  material  raised. 

Centrifugal  pumps  revolving  at  high  speeds  are  able 
to  raise  large  quantities  of  water  a  short  distance;  and 


284  GOLD  DREDGING 

within  the  small  radius  of  their  suction,  necessarily  close 
to  the  suction  pipe,  they  have  sufficient  power  to  raise 
mud,  fine  sand,  and  gravel. 

This  suction  might  raise  considerable  gold,  because 
the  velocity  of  the  water  entering  the  suction  is  greater 
than  the  velocity  with  which  gold  will  fall  by  gravity 
through  water. 

The  radius  of  suction  is  not  sufficiently  strong  on  its 
outer  periphery  to  draw  in  heavy  particles  of  gold  to  the 
central  point  of  suction,  while  it  is  sufficiently  strong  to 
draw  in  sand  and  mud.  When  the  sand  and  mud  are 
disturbed  the  heavy  particles  of  gold  begin  to  settle  and 
finally  reach  the  bottom,  in  which  position  it  is  difficult 
for  a  suction  pipe  to  dislodge  them,  particularly  if  there 
are  boulders  on  the  river  bottom,  or  crevices  into  which 
the  gold  may  sink.  Suction  pumps  raise  gravel  stones 
without  much  difficulty,  but  they  cannot  raise  coarse 
stones  and  boulders;  and  where  the  bottom  rock  is 
covered  with  these  by  natural  selection,  the  gold  falls 
in  between  them  and  is  lost,  unless  bed  rock  can  be 
cleaned  by  hand.  As  an  auxiliary  to  other  dredges 
where  the  bed  rock  is  hard  and  not  uneven,  they  might 
prove  useful  in  cleaning  up  gold  which  the  other  exca- 
vators cannot  recover.  The  suction  pump  as  a  gold 
dredger  has  a  very  narrow  range  of  usefulness  compared 
with  the  bucket  and  dipper.  Another  drawback  to 
centrifugal  pumps  is  the  height  to  which  they  can 
deliver  material  above  the  pump.  They  usually  are 
more  successful  at  the  suction  than  at  the  delivery  end 
of  the  pipe  line,  and  it  requires  excessive  power  to  raise 
water  and  material  higher  than  12  feet. 


CENTRIFUGAL  PUMPS  285 

(c)  Washing  and  Screening.  —  Screens  on  dredges,  if 
grizzlies  are  neglected,  are  either  of  the  revolving  or  the 
shaking  types. 

i.  The  revolving  screens  are  of  sheet  iron  with  holes 
ranging  from  .5  inch  in  diameter  at  the  receiving  end 
to  5  or  6  inches  diameter  near  the  discharge  end.  At 
present  screens  are  made  from  3  feet  to  4.5  feet  in  diam- 
eter and  from  20  feet  to  36  feet  long,  according  to  the  size 
of  the  buckets  and  capacity  of  the  dredge.  The  diam- 
eter of  the  screens  must  be  such  that  they  will  pass 
stones  as  large  as  the  buckets  will  bring  up.  To  prevent 
excessive  wear  on  screens,  it  is  a  better  plan  to  wash  all 
material  through  grizzlies  in  the  hopper  and  pass  all 
material  over  3  inches  in  diameter  either  to  the  tailings 
stacker  or  over  the  side  of  the  boat.  This  will  permit 
finer  sizing  of  the  material  going  to  the  sluices  and 
tables,  a  matter  as  important  in  sluicing  as  in  other 
kinds  of  concentration,  where  close  recoveries  are  made. 
The  length  of  the  screen  depends  on  the  kind  of  gravel 
to  be  washed.  In  every  case  it  should  be  such  that  no 
crowding  of  the  material  will  occur  and  prevent  it  being 
thoroughly  washed.  Ground  that  contains  water, 
rounded  stones,  and  much  clay,  should  be  passed  through 
rotary  screens,  as  they  are  better  washers  and  disin- 
tegrators than  shaking  screens.  Jets  of  water,  under 
pressure,  issue  from  pipes  inside  the  screen,  if  the  screen 
revolves  on  rollers ;  or  from  the  hollow  shaft  if  the  screen 
revolves  on  a  shaft.  This  water  washes  the  fine  material 
from  the  stones  and  through  the  screen  openings.  In 
most  cases  there  is  but  one  screen;  but  two  screens, 
one  inside  the  other,  are  better  adapted  to  sizing  and 


286 


ROTARY  SCREEN  287 

gold  saving.  The  first  screen  discharges  into  the  sluice, 
and  the  second  one  passes  all  material  to>  a  tank 
directly  under  it.  The  tank  is  a  distributing  box  that 
discharges  its  contents  uniformly  over  the  gold -saving 
tables.  In  case  there  is  but  one  screen,  the  large  stones 
discarded  at  the  end  go  to  the  tailings  stacker,  while 
the  material  passing  through  the  screen  openings  goes 
to  the  sluice,  and  the  fine  material  to  the  gold-saving 
tables. 

When  a  single  screen  is  used  the  size  of  the  openings 
must  be  such  that  no  gold  will  be  lost.  This  is  a  very 
uncertain  factor,  consequently  there  is  need  of  some 
large  openings,  and  the  necessity  of  turning  some  mate- 
rial into  the  sluice  box.  With  a  double  screen  the  lower 
screen  may  be  rotated  in  water  and  only  fine  stuff  sent 
to  the  tables,  while  the  discharge  may  be  delivered  to  the 
sluice.  Screens  should  be  constructed  in  sections,  in 
order  that  a  worn  part  may  be  replaced  without  dis- 
carding the  entire  screen. 

The  description  furnished  of  a  rotary  screen  arrange- 
ment is  the  author's  ideal.  As  now  constructed,  the 
material  that  passes  through  the  screen  in  most  cases 
passes  directly  to  a  sluice  box  containing  riffles  and  not 
over  a  gold-saving  table,  the  supposition  being  that  only 
coarse  gold  is  in  the  placer. 

2.  Shaking  Screens.  —  It  has  been  stated  that  rotary 
screens  are  better  for  clayey  material  and  round  stones 
than  shaking  screens.  Clean  gravel  with  little  clay, 
and  material  carrying  fine  gold,  are  suited  to  shaking 
screens.  Rough  stones  are  handled  with  equal  facility 
by  either  kind  of  screen. 


288  GOLD  DREDGING 

Shaking  screens  are  given  sufficient  fall  and  screening 
area  to  permit  of  the  gold  being  thoroughly  washed  from 
the  rocks  before  the  latter  are  discharged  to  the  tailings 
stacker.  Fig.  83  shows  a  shaking  screen  with  gold  tables. 
In  the  illustration  the  shaking  screen,  which  has  an  area 
of  from  600  to  700  square  feet,  works  in  the  box,  a. 

From  a  series  of  openings  above  the  screen,  water 
is  projected  upon  all  parts  of  the  screen,  washing  and 
disintegrating  the  material  before  the  finer  particles  pass 
into  the  chute,  b,  leading  to  the  distributor,  ct  placed 
below  the  screens  and  above  the  gold-saving  tables,  d. 
The  coarse  material  passes  out  at  the  lower  end  of  the 
screen  into  a  hopper,  e,  leading  to  the  tailings  stacker. 

The  fine  material  which  passes  over  the  tables  is 
carried  to  sluice  boxes,  which  discharge  the  material 
about  20  feet  beyond  the  stern  of  the  dredge.  The 
sluice  boxes  are  also  fitted  with  riffles,  and  if  there  is 
much  sand  they  deliver  their  material  to  a  centrifugal 
pump  for  final  distribution.  In  this  case  the  pump  dis- 
charge pipe  is  placed  on  the  stacker  arm  so  that  the  sand 
is  delivered  over  the  top  of  the  gravel  (see  Fig.  81).  Simi- 
lar arrangements  may  be  necessary  with  a  rotary  screen, 
if  gold  tables  are  used  in  addition  to  sluice  boxes. 

(d)  Gold-saving  Arrangements.  —  Before  an  intelligent 
conception  can  be  reached  of  the  kind  of  gold-saving 
appliances  to  adopt,  the  fineness  of  the  gold  going  to 
the  riffles  must  be  determined.  The  next  important 
consideration  is  the  material,  and  the  best  arrangements 
to  install  to  wash  it  thoroughly.  As  too  much  water  is 
almost  as  bad  as  too  little  water,  experiments  should  be 
made  to  ascertain  the  minimum  quantity  of  water 


GOLD-SAVING  TABLES 


289 


required  for  a  maximum  recovery.  Any  neglect  of  one 
of  these  three  important  items  may  make  the  sluice  or 
table  riffles  but  mediocre  gold-saving  appliances. 

Hungarian  riffles  or  gold  tables  such  as  are  shown  in 


FIG.  84. 

Fig.  84  are  used  on  dredges  where  coarse  material  is 
separated  from  the  fine  material  before  the  latter  passes 
over  the  tables.  They  require  considerable  mercury, 
and  are  fairly  effective  when  given  a  grade  of  about 
1 8  inches  in  12  feet.  They  are  placed  below  the  sluice- 
box  grizzlies  or  distribution  boxes,  and  are  virtually 
undercurrents.  The  grizzlies  do  not  allow  anything 
larger  than  J  inch  diameter  to  go  to  these  tables. 

The  riffles  most  generally  used  are  of  the  Hungarian 
type    as    previously   illustrated,    but   are   supplemented 


2QO  GOLD  DREDGING 

by  the  riffle  shown  in  Fig.  85,  which  is  made  up  as  fol- 
lows: First  an  iron  floor  upon  which  is  placed  a  layer 
of  calico.  Above  this  in  the  order  named  is  a  layer  of 
ordinary  cocoa  matting,  and  expanded  metal.  The  metal 
is  fastened  in  such  a  manner  it  can  readily  be  removed 
when  it  is  desired  to  wash  the  cloths.  Every  few  days 
the  expanded  metal,  which  is  used  to  keep  the  matting 


FIG.  85. 

flat  and  hold  it  down,  is  taken  up,  and  the  cloths  washed 
in  a  box  to  collect  the  fine  gold,  after  which  they  are 
returned  to  the  tables,  and  the  expanded  metal  fastened 
in  place.  These  tables  are  considered  the  best  fine  gold- 
saving  devices,  and  are  widely  used  in  consequence. 

In  case  there  is  much  black  sand,  the  matting  becomes 
clogged  so  that  the  gold  cannot  settle,  and  if  more  water 
is  run  over  the  tables  to  clean  them  of  sand,  the  gold 
goes  with  the  sand.  To  prevent  the  accumulation  of 
black  sand  it  must  be  removed  before  it  reaches  the 


GOLD-SAVING  DEVICES  291 

matting.  Owing  to  the  limited  length  of  sluice  boxes 
on  dredges  and  their  narrow  width,  undercurrents  or 
gold-saving  tables  are  made  wide;  on  some  dredges  they 
occupy  as  much  as  1200  square  feet  of  space.  There 
are  no  better  gold-saving  devices  in  existence  than  are 
found  on  dredges,  consequently  the  loss  must  be  due  to 
some  extent  to  imperfect  washing  arrangements,  or  to 
allowing  too  much  material  to  flow  over  the  table  at 
one  time.  A  steady  flow  of  water  is  imperative  in  such 
work,  even  should  there  be  an  uneven  flow  of  material. 

If  the  water  passing  over  the  tables  contains  much 
alumina  or  much  magnesia,  it  will  slick  the  tables  in 
a  very  short  time  and  prevent  anything  but  heavy  gold 
adhering.  Recognizing  the  necessity  of  thoroughly 
washing  the  gold,  and  at  the  same  time  comminuting 
adhering  substances  to  such  an  extent  that  they  would 
be  held  in  suspension  by  the  water,  the  writer  suggested 
in  1897  that  the  log  washer  be  adopted  on  dredges. 
The  success  attained  by  the  log  washer  in  the  South  has 
verified  the  author's  expectations.  In  some  cases  the 
screens  on  dredges  have  been  arranged  to  pass  all  fine 
material  to  centrifugal  pumps  for  additional  washing, 
and  these  pumps  have  delivered  the  washed  material 
to  the  sluices.  There  are  several  objections  to  this 
method  of  washing:  First,  there  is  too  much  water  de- 
livered to  the  sluices;  second,  the  centrifugal  pump  is  a 
poor  washing  contrivance;  third,  there  is  an  unnecessary 
waste  of  power ;  fourth,  the  material  is  necessarily  deliv- 
ered in  an  intermittent  manner  to  the  pump  and  to  the 
sluices,  consequently  more  water  than  is  needed  must 
be  pumped.  Sluice  boxes  on  dredges  are  about  of  the 


292  GOLD  DREDGING 

same  construction  as  in  ordinary  sluicing,  except  that 
they  are  often  of  iron.  Where  the  rotary  screen  is  used 
without  gold-saving  tables  the  sluice  boxes  are  made  long, 
as  shown  in  Fig.  79,  and  in  some  instances  they  extend 
back  to  independent  barges,  that  support  them  in  such  a 
way  that  their  length  can  be  materially  increased,  and  an 
undercurrent  placed  in  the  sluice  line. 

(e)  The  Stacker. — There  are  two  kinds  of  rock  stackers 
in  use,  both  of  which  are  of  the  endless  belt  type.  The 
stacker  arm  is  steel  trussed,  and  is  raised  or  lowered  as 
occasion  demands  by  wire  ropes  that  are  worked  by  a 
small  hoisting  engine.  The  ropes  are  fastened  to  the 
bail  of  the  stacker  arm  and  pass  through  pulleys  sus- 
pended on  the  cross  piece  of  the  stern  gantry. 

At  the  top  and  bottom  of  the  stacker  arm  there  are 
sprocket  wheels  or  belt  pulleys;  the  lower  one  in  most 
cases  is  the  driver,  while  the  upper  one  is  the  driven 
wheel  or  pulley.  This  arrangement  is  not  as  economical 
in  the  use  of  power,  or  as  satisfactory,  as  where  the  upper 
pulley  wheel  is  the  driver.  The  rock  stacker  is  par- 
ticularly useful  in  ground  where  there  are  many  stones, 
and  in  places  as  much  as  75  per  cent  of  the  material  is 
coarse.  It  also  aids  in  saving  gold  by  keeping  stones 
out  of  the  sluice  boxes,  and  in  this  way  shortening  their 
length. 

The  bucket  conveyor  on  the  tailings  ladder  is  said  to 
last  longer  than  the  belt  conveyor,  and  to  raise  material 
at  a  higher  angle.  It  requires,  however,  more  power 
to  run,  is  more  expensive  in  first  cost,  and  less  easily 
repaired,  than  the  belt  conveyor.  Belt  conveyors  have 
carried  500,000  tons  of  sharp  rock  without  wearing  out 


TAILING  STACKER  293 

or  needing  repairs;  in  fact,  they  are  preferable  to  chain 
conveyors  where  the  angle  of  elevation  is  not  so  high 
as  to  cause  the  material  to  run  back,  or  about  24  degrees. 
The  tailings  stacker  must  be  long  enough  to  raise  the 
coarse  material  to  an  elevation  and  to  a  distance  behind 
the  dredge  that  it  will  not  run  back  into  the  diggings. 

When  fine  material  is  to  be  put  out  of  the  way,  the 
pump  pipe  is  attached  to  the  tailings  ladder,  and  the 
pump  must  have  sufficient  power  to  throw  the  sand  and 
water  over  the  top  of  the  coarse  tailing  pile.  When  the 
pump  is  used  to  dispose  of  the  tailing  the  tail  sluice  is 
not  needed,  as  all  material  that  passes  down  the  sluice 
box  goes  to  the  pump. 

(/)  The  Power  Plant. — Electrical  power,  when  it  may 
be  obtained  readily  and  cheaply,  is  preferred  to  steam- 
power.  Where  two  or  more  dredges  are  in  close  prox- 
imity, it  is  more  economital  to  locate  a  steam  boiler 
plant  on  shore  and  transmit  electricity  to  the  dredges, 
than  to  have  engines  and  boilers  on  the  boats.  It  takes 
considerable  handling  to  place  fuel  on  board  the  boat, 
and  it  is  a  well-known  fact  that  several  small  engines  are 
wasteful  of  steam  to  a  greater  extent  than  a  large  auto- 
matic cut-off  engine  when  generating  electricity. 

There  will  also  be  a  loss  of  steam  due  to  condensation, 
on  a  dredge,  as  the  engines  must  be  placed  at  some  dis- 
tance from  the  boilers.  In  addition  to  the  disadvantages 
named,  the  boiler  is  in  the  way  on  the  boat,  unless  addi- 
tional length  is  added  for  its  accommodation.  In  locali- 
ties where  there  are  ditch  lines,  electrical  generating 
plants  can  be  cheaply  installed  by  using  nozzles  and 
impulse  water  wheels.  In  other  localities  a  small  dam 


294  GOLD  DREDGING 

and  flume  can  be  cheaply  constructed  to  furnish  water- 
power  for  generating  electricity. 

The  power  required  for  a  3  cubic  foot  bucket  dredge 
is  about  as  follows: 

For  driving  the  buckets  ......  75  horse-power. 

To  drive  a  lo-inch  centrifugal  sluice 

pump  50  horse-power. 

The  revolving  screen  requires  ...  20  horse-power. 
To  drive  an  8-inch  centrifugal  screen 

pump 30  horse-power. 

To  move  the  scow 20  horse- power. 

Auxiliary  pumps,  power  for  tailings  stacker,  electric 
light  plant,  and  sluice  pump  for  tailings,  would  require 
considerable  additional  power. 

In  the  above  estimation,  which  does  not  include  the 
power  required  for  a  tailings*  stacker  or  sand  pump,  it 
will  be  observed  that  80  horse-power  or  41  per  cent  of 
the  power  is  used  for  washing  purposes,  and  but  38  per 
cent  for  digging  purposes. 

The  object  in  using  centrifugal  pumps  is  to  obtain  a 
large  supply  of  water,  and  this  is  accomplished  at  the 
expense  of  power.  The  pumps  are  cheap  and  easily 
kept  in  repair;  however,  it  is  probable  that  by  using  com- 
pound centrifugal  pumps,  the  power  would  be  econo- 
mized particularly  in  the  spraying  pumps,  where  force  is 
desired  rather  than  quantity.  A  reduction  in  the  quan- 
tity of  water  used  in  sluicing  would  often  be  found  bene- 
ficial. The  object  is  to  transport  the  material  and  not 
flush  the  sluice  boxes. 

The  following  table  furnished  Mr.  D'Arcy  Weatherbee 


DREDGE  MACHINERY 


295 


by  D.  P.  Cameron  of  the  Western  Engineering  and 
Construction  Company,  who  are  agents  for  the  Bucyrus 
Company,  gives  an  idea  of  the  weight  of  a  3j-foot 
Bucyrus  dredge. 


Name  of  Part. 

Total 
Weight 
Lbs. 

Number  of  Pieces  and  their  Weight. 

Upper  tumbler      ... 

6,500 

Can  be  cut  in  20  pieces,  one  of 

which  will  weigh  1,000  lb.,  the  rest 

will  be  below  300  lb. 

Lower  tumbler     .... 

4>5°° 

Can  be  cut  in  13  pieces,  three  of 

which  will  be  about  700  lb.,  the 

rest  below  300  lb. 

Digging  ladder     .... 

28,000 

Two  pieces  of  600  lb.,  the  rest 

about  300  lb. 

Digging  buckets  (3$  ft.). 

83,000 

Bottom  about  320  lb.,  each  hood 

135  lb.,  lip  120  lb. 

Screen,  stacker  and  parts 

16,000 

Eight  pieces  would  weigh  about 

600  lb.  each,  all  other  parts  350  lb. 

and   less;    70  per  cent  less  than 

300  lb. 

Gearing     .    ,    

30,000 

Eight  parts  would  weigh  about 

700  lb.  each,  the  rest  from  350  lb. 

down;  50  per  cent  less  than  300  lb. 

Engine  or  motors     .    .    . 

15,000 

Two  pieces  about  1,000  lb.;  two 

pieces  about  600  lb.;  50  per  cent 

below  350  lb. 

Boilers   

8  soo 

All  below  350  lb. 

Pumps    

w»3*** 

too 

Winches     

owv^ 
42,000 

Two  pieces  600  lb.     All  other 

parts  below  350  lb. 

Other  parts 

7  600 

All  below  3^0  lb. 

Spuds.  —  On  the  bucket  dredge  there  are  two  spuds 
42  X  1 8  inches  X  50  feet  long  with  steel  points  at  the 
lower  end.  The  spuds,  which  are  raised  by  machinery 
and  lowered  by  gravity,  serve  to  move  the  boat,  or  hold 
it  steady  when  dredging.  To  move  the  boat  forward  or 
backward  the  spuds  are  alternately  raised  and  dropped, 
after  the  engineer  swings  the  boat  by  means  of  cables 


296  GOLD  DREDGING 

passing  around  the  front  corners  of  the  boat  and  attached 
to  lateral  anchorages. 

When  dredging,  one  of  the  spuds  rests  on  the  bottom 
and  forms  a  pivot,  around  which  the  boat  is  swung  as 
the  gravel  is  taken  up.  The  buckets  thus  take  off  a 
segment  of  dirt  about  6  inches  deep  and  8  feet  wide, 
and  after  each  swing  of  the  dredge  around  the  spud  the 
ladder  is  lowered  6  inches.  The  lowering  of  the  ladder 
continues  until  bed  rock  is  reached.  The  bed  rock, 
if  yielding,  is  torn  loose  and  brought  up  until  barren 
of  gold. 

The  dipper  dredge  is  supplied  with  4  spuds,  one  near 
each  corner  to  prevent  the  barge  from  swinging  and 
from  tipping.  The  spuds  have  racks,  and  are  raised 
by  pinions  driven  by  machinery. 

The  boat  is  moved  forward  by  ropes  attached  to 
anchors  and  winches.  The  boom  swings  180  degrees; 
consequently  the  dipper  can  dig  quite  a  semicircle,  and 
to  a  depth  depending  on  the  length  of  the  dipper  arm, 
without  changing  the  position  of  the  boat. 


CHAPTER    XI. 

TRACTION  DREDGES:  DRY  PLACER  MINING  MACHINES. 

STEAM  shovel  excavators  have  been  mentioned  under 
the  caption  "  Exploiting  Placers."  In  that  connection, 
however,  there  was  sufficient  water  for  the  excavation, 
but  a  lack  of  dumping  ground.  Traction  dredges  are 
for  exploiting  placers  where  little  water  exists,  and  where 
conditions  are  unfavorable  for  sluicing,  dredging,  or  the 
use  of  other  systems  of  placer  mining. 

To  determine  whether  this  method  of  work  would 
be  profitable,  exploration  and  prospecting  must  be 
carefully  carried  on.  Sure  thing  placers  do  not  exist 
in  all  localities  as  they  do  in  Oroville  and  some  other 
districts,  therefore  where  one  test  hole  was  put  down 
in  every  four  or  five  acres,  one  and  probably  more 
holes  will  be  required  for  every  acre.  The  land  is 
therefore  divided  up  into  sections,  and  in  some  cases 
a  Keystone  drilling  machine  takes  samples  just  ahead 
of  the  dredger  in  order  to  work  the  richest  ground. 
When  communicating  with  manufacturers  of  traction 
dredges  the  following  information  in  detail  is  required 
by  them: 

The  lay  of  the  ground;  that  is,  whether  it  is  in  a 
gulch,  an  old  river  bed,  lake  bed,  or  small  valley; 

The  grade  of  the  bed  rock  if  that  can  be  determined, 
and  if  not,  the  slope  of  the  surface; 

297 


298 


TRACTION  DREDGES 


How  high  the  material  must  be  raised  in  order  to 
obtain  sufficient  sluice  fall; 

The  kind  of  material  to  be  washed,  i.e.,  whether 
coarse  or  fine; 

The  depth  from  the  surface  and  the  thickness  of 
the  pay  streak;  this  will  furnish  practical  information 
regarding  the  quantity  of  waste  material  that  must  be 
handled  and  disposed  of; 

The  quantity  of  water  at  command  and  the  distance  it 
must  be  piped; 

Water  in  cut,  if  any,  and  how  deep; 

A  contour  map  of  the  ground  is  very  desirable. 


WB 


FIG.  86. 


The   end   outlines   of  a   traction  dredge  with  plain 
swinging  circle  are  shown  in  Fig.  86. 

The   dredge   platform   rests   on   two   trucks,  a,  that 


TRACTION  EXCAVATORS 


299 


have  a  27-inch  gauge  and  are  moved  by  the  motive 
power  used  to  drive  the  other  machinery.  The  dis- 
tance, WB,  from  center  to  center  of  the  tracks  is  from 
12  to  14  feet.  The  circle,  b,  is  for  swinging  the  boom,  c. 
The  length  of  the  boom  required  depends  upon  the 
height  of  the  dump,  or  HD,  above  the  dredge  track, 
and  the  distance,  CC,  from  the  center  of  the  machine 


FIG.  87. 

to  the  center  of  the  dump.  The  length  of  the  dipper 
arm,  d,  depends  upon  the  depth  of  the  cut  and  the 
height,  HD.  The  machinery  on  the  dredge  when  the 
dredge  is  not  self-contained  consists  of  an  engine  for 
working  the  boom,  a  thrust  engine,  e,  on  the  boom,  and  a 
boiler.  The  capacity  of  the  dredge  is  governed  by  the 


300  TRACTION  DREDGES 

power  of  the  digging  apparatus  and  the  size  of  the 
dipper. 

Self-contained  dredges  in  addition  to  the  machinery 
mentioned  will  require  power  for  hoisting  the  car  to 
the  dump,  revolving  the  screen,  and  working  the  tailings 
stacker. 

Fig.  87  is  one  of  a  number  of  traction  dredges  con- 
structed by  the  Marion  Steam  Shovel  Company.  It 
is  a  rear  view.  The  skip,  a,  is  loaded  on  the  bank  by  the 
shovel,  b,  and  is  then  hoisted  and  dumped  automati- 
cally into  a  hopper.  The  ore  is  washed  into  screen,  c, 
the  fine  ore  going  to  the  sluice,  d\  that  which  passes 
out  of  the  end  of  the  screen  to  tailings  stacker,  e;  and 
the  very  coarse  goes  over  the  side  of  the  dredge. 

The  platform  rests  on  four  trucks.  The  machinery 
is  so  arranged  that  it  is  not  crowded,  and  comes  within 
the  center  of  gravity  of  the  car  platform,  thereby  doing 
away  with  jackspuds  and  braces,  which  are  necessary 
when  there  is  but  a  single  track  and  a  narrow  platform. 
The  platform  sills  are  of  wood  or  steel  girders,  stiffened 
by  ties  of  iron,  forming  a  king  or  queen  truss  extending 
the  entire  length  of  the  sills. 

The  trucks,  platform,  and  machinery  will  weigh 
between  40  and  70  tons. 

Single-track  traction  dredges  have  been  constructed 
to  run  on  a  4-foot  8f-inch  standard  railroad  gauge, 
in  order  that  all  parts  might  be  assembled  at  the  shops 
and  the  machines  transported  to  their  destination. 
There  is  not  much  gained  by  this  construction,  from  the 
fact  that  it  is  not  often  that  placers  suitable  for  this  method 
of  exploitation  are  found  near  railroads;  and  to  lay  a 


WORKING  TRACTION  DREDGES  301 

temporary  railroad  to  the  placer  ground  is  expensive, 
even  if  the  dredge  contains  its  own  motive  power. 

Where  single-track  dredges  are  used,  jack  arms  and 
side  braces  must  be  adopted  in  order  to  keep  the 
machines  upright,  and  prevent  the  dipper  when  swinging 
from  straining  the  parts  of  the  car  body. 

The  tracks  for  traction  dredges  must  be  kept  as  near 
bed  rock  as  possible,  and  at  the  same  time  the  machin- 
ery should  be  kept  level,  to  prevent  undue  wear  on  the 
journals  as  well  as  keep  the  water  in  the  boiler  in  proper 
position.  These  machines  are  said  to  do  work  on 
considerable  incline,  but  they  are  not  built  for  that 
purpose,  and  will  save  money  for  the  operator  if  kept 
level.  The  trouble  with  the  first  machines  of  this  dry- 
placer  type  was  that  they  cost  as  much  to  keep  in  repair 
as  the  value  of  the  gold  saved,  and,  as  they  were  dis- 
carded, probably  more. 

Mining  with  such  machines  will  depend  upon  the 
water  supply.  .  Beside  a  river  bank  or  near  some  stream 
they  should  work  satisfactorily,  but  in  situations  where 
water  is  not  abundant  they  must  be  economical  in  its 
use.  If  it  be  necessary,  85  per  cent  of  the  water  needed 
for  working  these  machines  may  be  impounded  and 
used  over  again,  thus  requiring  but  15  per  cent  of 
the  total  quantity  to  be  fresh. 

The  water  supply  must  in  all  cases  be  in  quantity 
from  8  to  10  times  the  amount  of  dirt  excavated. 

Thus,  if  one  cubic  foot  of  dirt  be  washed  per  minute, 
there  will  be  required  from  8  to  10  cubic  feet  of  water 
needed  per  minute;  of  this  amount  from  6.8  to  8.5  cubic 
feet  may  be  used  over;  thus  the  actual  fresh  supply 


302 


TRACTION  DREDGES 


required     will     be    from    1.2    to    1.5     cubic    feet    per 
minute. 

With  first-class  washers  the  amount  of  water  required 


should  not  be  more  than  8  cubic  feet  per  minute. 

The  dirt  is  excavated  by  an  ordinary  steam  shovel 
whose   dipper   is   capable   of   handling   hard    pan    and 


TRACTION  DREDGE  WASHERS  303 

ordinary  hard  material,  or  by  the  clam  shell  bucket. 
The  dipper  of  the  shovel  works  from  the  arm  of  a 
derrick,  so  arranged  in  this  instance  as  to  have,  an  arm 
long  enough  to  deliver  the  material  directly  over  the 
hopper,  H,  Fig.  88.  The  derrick  is  mounted  on  a  turn- 
table which  is  made  to  revolve  by  machinery  nearly 
140-  degrees,  or  until  the  dipper  is  directly  over  the 
hopper. 

The  dipper,  being  required  to  excavate  hard  cemented 
material,  must  combine  strength  and  power.  The  boom 
for  the  bucket  arm  is  made  to  conform  to  the  depth  of 
the  alluvions.  For  example,  a  35-foot  boom  will  raise 
material  18  to  20  feet  above  the  track  and  make  a  cut 
35  feet  in  width. 

With  the  exceptions  of  the  length  of  arm  and  the 
turn,  the  excavating  part  of  the  machine  differs  very 
little  from  the  ordinary  railroad  steam  shovel.  Where 
the  washing  machinery  is  on  trucks  at  the  back  or  at 
the  side  of  the  shovel,  the  swing  may  be  halfway  round. 
In  some  instances  the  shovel  is  independent  of  the 
washing  machine,  the  latter  being  stationary  and  the 
shovel  only  advancing.  Where  the  washer  is  stationary, 
tram  cars  or  traveling  conveyors  are  used  to  carry  the 
material  from  .the  shovel  to  the  washer.  Dippers  of 
the  scoop  shape  are  generally  used,  although  clam 
shell  buckets  will  answer  in  some  cases.  Scoop  dippers 
made  to  hold  ij  cubic  yards  will  when  filled  probably 
not  average  over  i  cubic  yard  of  dirt.  They  could 
under  favorable  conditions  make  six  scoops  and  deliver 
six  buckets  into  the  hopper  in  five  minutes,  or  72  cubic 
yards  per  hour;  however,  at  this  rate,  under  ordinary 


304  TRACTION  DREDGES 

circumstances,  the  washer  could  not  handle  the  material, 
consequently  i  cubic  yard  per  minute  should  be  assumed 
for  calculations.  Where  there  is  plenty  of  water  the 
shovels  can  be  increased  in  size  up  to  2j  cubic  yards, 
but  the  whole  plant  must  necessarily  be  enlarged  in 
proportion. 

Wherever  the  hopper  for  the  reception  of  the  ex- 
cavated material  projects  beyond  the  side  of  the  car 
it  must  be  strongly  braced;  further,  the  structure  is 
subjected  to  considerable  vibration  and  strain  by  the 
sudden  unloading  of  a  cubic  yard  of  material.  Another 
disadvantage  is  that  the  hoppers  require  too  much  fall 
for  the  height  of  the  machine,  necessitating  the  use  of 
power  in  raising  the  waste  material  to  the  dump  and 
the  pulp  to  the  sluices.  To  avoid  the  strain  from  side 
hoppers,  some  makers  place  the  washing  and  elevating 
apparatus  upon  separate  cars.  It  is  possible  by  the 
use  of  a  wide  platform  and  the  double  truck  system 
mentioned  to  raise  the  washing  machinery  and  allow 
gravity  to  dispose  of  the  coarse,  medium,  and  fine 
material  without  recourse  to  elevating  machinery  for 
that  purpose. 

To  accomplish  this  the  washer  is  constructed  on  the 
car  platform  and  the  hopper  placed  for  the  reception 
of  excavated  material  above  the  washer  but  within  the 
center  of  gravity  of  the  car. 

Another  system  of  raising  the  material  to  the  hopper 
is  where  a  double  inclined  track  is  laid  from  the  ground 
to  the  top  of  the  mill.  Upon  this  track  two  skips  run; 
as  the  loaded  skip  ascends,  the  empty  skip  descends. 
The  power  for  raising  the  loaded  skip  is  derived  from 


TRACTION   DREDGE  WASHERS  305 

the  engines  which  work  the  excavator.  The  material 
having  been  dumped  automatically  into  the  hopper, 
it  is  washed  down  over  coarse  screen  bars. 

That  portion  of  the  material  too  coarse  to  pass  the 
bars  goes  directly  to  the  dump  by  gravity;  that  portion 
which  passes  the  grizzlies  falls  into  the  screen,  where 
it  is  thoroughly  washed  of  fine  material,  which  falls 
into  the  sluices,  while  that  portion  too  coarse  for  the 
sluices  moves  by  gravity  to  the  dump.  This  system 
disposes  of  all  tailings  and  pulp  by  gravity,  thus  making 
an  economical  and  power-saving  system,  by  doing 
away  with  elevator  engines  and  one  pump,  as  well  as 
the  elevating  and  conveying  apparatus. 

The  hoppers  in  dry  placer  mining  machines  should 
be  so  arranged  that  the  material  may  be  washed  by 
water  from  pipes,  P,  surrounding  the  hopper,  and 
through  iron  bars  forming  the  floor  of  the  hopper. 
This  will  allow  the  action  of  the  screen  to  more  thor- 
oughly disintegrate  the  material.  The  coarse  stuff 
remaining  on  the  bars  can  be  removed  by  mechanism 
down  over  a  stone  chute.  The  screen  should  be  of 
two  compartments.  The  inner  compartment  (being 
fed  by  streams  of  water  to  further  soften  and  wash  the 
material)  should  allow  the  passage  of  all  stuff  up  to 
J  inch  diameter  into  the  outer  compartment.  This 
outer  screen  should  be  arranged  to  revolve  in  water, 
thus  further  washing  and  disintegrating  the  material. 
The  pulp  from  the  washing  hopper  is  drawn  off  by  a 
centrifugal  pump  and  raised  to  the  sluices  containing 
the  riffles. 

The  coarse  stuff  from  the  inner  circle  of  the  revolving 


306 


TRACTION  DREDGES 


screen  falls  into  elevators  at  B,  Fig.  63,  and  is  conveyed 
by  them  to  the  dump. 

In  the  illustration,  Fig.  89,  which  is  the  Traction  Dredge 
of  the  Bucyrus  Company,  the  hopper  is  supplied  with 
water  from  pipe,  P,  which  washes  the  material  down 


FIG.  89. 

into  the  screen;  a  second  hopper,  H',  receives  the 
washed  material  containing  the  gold.  The  pipe,  SP, 
Fig.  62,  is  the  pipe  for  discharging  the  pulp  into  the 
sluice  box  from  the  pump.  F  is  the  A-shaped  head 
frame  which  supports  the  bucket  ladder,  L,  over  which 
the  loaded  tailing  buckets  travel  from  the  screen  dis- 
charge to  the  coarse  tailing  dump. 

The  sluice  boxes  are  not  shown.  They  may  be 
extended  a  considerable  distance  from  the  machine, 
but  if  water  is  scarce  the  material  is  discharged 
where  the  water  may  drain  into  a  sump.  With 
plenty  of  water  a  one  per  cent  grade  will  carry  off 


TRACTION  DREDGE  MACHINERY  307 

the  material  in  the  sluices,  which  are  provided  with  riffles. 
The  first  few  sections  of  the  sluice  box  should  be  of  light 
steel,  so  that  they  may  be  readily  handled  and  made 
water  tight. 

The  Chicago  Mining  Machine  has  a  complicated 
screening  arrangement,  and  a  short  riffle  sluice  on  the 
machine  itself.  The  tailings  from  the  riffle  sluice  are 
discharged  upon  the  coarse  tailings  dump.  This  com- 
pany pays  particular  attention  to  washing  the  material 
in  the  revolving  screen,  which  has  in  its  inner  compart- 
ment a  spiral  conveyor.  No  pitch  at  all  is  given  to 
the  screen,  the  material  being  moved  forward  by  the 
conveyors. 

The  list  of  machinery  for  such  dry  placer  machines 
comprises  a  boiler  of  the  upright  or  locomotive  type, 
engines  to  work  the  shovel  and  derrick,  engines  to  run 
the  washer  and  conveying  machinery,  pumps  to  supply 
the  water  to  the  washer  and  sluices. 

The  horse-power  necessary  to  work  the  shovel  is  fur- 
nished by  a  double  8  X  lo-inch  engine,  and  may  be 
rated  at  25  H.P.  To  run  the  elevating  and  washing 
machinery  6  X  6-inch  double  engines  are  used,  which 
may  be  rated  at  10  H.P.  Centrifugal  pumps  are  used, 
and  they  will  require  15  H.P.  each  for  their  independent 
engines.  At  times  an  auxiliary  steam  pump  may  be 
required,  and  in  some  instances  it  is  part  of  the  system  to 
use  it  for  pumping  water  to  the  hopper  and  washer, 
leaving  the  centrifugal  pump  to  work  the  pulp  only. 
The  screens,  elevators,  sprockets,  chains,  rollers,  etc., 
will  vary  in  style  and  make,  according  to  the  machine 
manufacturers'  patterns,  and  are  therefore  not  described. 


308  TRACTION  DREDGES 

With  traction  dredges  whose  rated  capacity  is  i  cubic 
yard  per  minute,  it  is  safe  to  estimate  that  in  one  hour  out 
of  every  ten  the  machine  must  be  stopped  for  repairs, 
or  for  advancing,  or  other  cause,  which  will  place  the 
average  duty  at  500  cubic  yards  per  day.  The  fuel  will 
generally  be  wood,  at  $4.50  per  cord,  and  two  cords 
daily,  or  $9,  for  50-H.P.  engines.  Wear  and  tear,  oil  and 
waste,  will  amount  to  3  cents  per  yard,  or  $15  per  day. 
The  labor  of  5  men,  averaging  $3  per  day  each,  $15, 
making  the  total  expenses  of  running  such  a  plant,  not 
including  quicksilver  lost,  $40,  or  8  cents  per  cubic  yard. 

This  estimate  of  running  expenses  does  not  include 
the  superintendent  and  his  expenses,  or  the  transporta- 
tion of  the  gold  dust.  The  latter  two  items  will  amount 
to  $10  daily  at  least,  bringing  the  cost  to  10  cents  per 
cubic  yard. 

The  amount  of  gold  collected  will  depend  upon  the 
machine  construction  and  the  superintendent;  a  poor 
machine  will  not  aid  a  good  superintendent.  Suppose 
a  machine  weighs  50  tons,  or  100,000  pounds;  the  cost 
at  the  mine  will  approximate  7  cents  per  pound,  unless 
some  patents  in  connection  with  it  raise  it  considerably 
higher.  Suppose  the  value  of  the  gravel  is  20  cents  per 
cubic  yard,  and  90  per  cent  of  the  value  is  recovered. 
The  profit  under  the  conditions  cited  would  be  $5000 
the  first  year  if  the  entire  year  could  be  worked  through. 
There  is  no  doubt  but  that  traction  dredges  are  better 
calculated  for  some  conditions  than  other  methods  of 
washing  gold,  and  that  they  have  not  received  more 
general  attention  is  due  to  the  exploitation  of  floating 


DRY  PLACER  EXPLOITATION  309 

dredges,  and  the  unwillingness  of  operators  in  this  line 
to  experiment  with  anything  new. 

What  has  been  said  previously  regarding  the  thorough 
exploration  of  placer  deposits  applies  here.  The  loca- 
tion of  the  deposit  with  reference  to  the  nearest  railroad 
station,  and  the  condition  of  the  roads  leading  to  it  for 
transporting  machinery,  are  matters  of  importance.  In 
case  it  is  impossible  to  transport  the  boiler,  power 
may  possibly  be  transmitted  by  electric  wires  from  a 
distance. 

Several  reliable  steam  shovel  concerns  furnish  the 
machinery  and  plans  for  traction  dredges.  These  com- 
panies are  not  willing  to  build  machines  for  placer  work 
unless  they  are  assured  beforehand,  by  examination  and 
thorough  exploration  of  their  own  or  some  other  reliable 
engineer,  that  the  diggings  are  of  sufficient  value  to  make 
the  enterprise  a  success.  The  Bucyrus  and  Marion 
Steam  Shovel  companies  state  this. 

From  the  very  nature  of  placer  mines  —  that  is,  the 
cemented  state  of  the  gravel  —  it  follows  that  if  the 
material  can  be  broken  up  before  it  reaches  the  sluices 
or  the  dipper  the  chances  for  gold  recovery  are  improved. 
There  are  many  instances  where  the  ground  is  so  tena- 
cious or  the  banks  so  high  that  it  is  thought  advisable  to 
run  in  tunnels  and  counters  to  break  it  up  with  powder. 

Experience  in  breaking  down  gravel  banks  with  pow- 
der will  satisfy  most  people  that  small  blasts  on  the  edges 
of  a  bank  are  more  economical  in  the  use  of  powder  and 
more  effectual  in  breaking  material  fine  than  large 
blasts  in  tunnels.  For  shovel  work,  a  blast  which 
merely  jars  the  surface  and  does  not  throw  out  the 


310  '  TRACTION  DREDGES 

material  will  afford  easy  working  for  the  dipper,  and,  what 
is  more  essential,  will  permit  the  ground  to  be  washed 
much  easier.  The  effect  of  the  shot  seems  to  be  that  of 
rending  the  whole  mass  of  dirt  without  displacement, 
hence  it  is  very  advantageous  where  water  is  scarce  and 
steam  shovels  are  used.  If  the  dipper  delivers  large 
lumps  of  cemented  gravel  of  a  tenacious  character  to 
the  hopper,  considerable  water  must  be  used  to  wash 
it  down  so  fine  that  it  will  disintegrate  readily;  but  water 
in  such  cases  is  an  item,  and  consequently  any  method 
which  will  bring  the  material  to  the  hopper  in  such  shape 
as  to  reduce  the  quantity  of  water  to  a  minimum  will 
help  the  washing  and  recovery  that  much,  and  further 
increase  the  capacity  of  the  machine. 

Small  blasts  are  considered  to  require  more  powder 
than  large  blasts  in  comparison  with  the  proportion 
of  the  ground  they  disturb.  This  is  true  to  a  certain 
extent,  but  it  must  be  borne  in  mind  that  the  ground 
is  more  thoroughly  rended  by  small  blasts  than  by 
large  ones,  and  it  is  the  results  in  detail  which  are 
sought;  in  other  words,  the  quality  rather  than  the 
quantity  for  traction  dredges. 

Dry  Placer  Machines  are  those  constructed  to  work 
without  water,  consequently  they  cannot  be  as  effectual 
as  machines  using  water.  There  are  many  placers  in 
Nevada,  Arizona,  New  Mexico,  and  Lower  California, 
where  water  is  lacking,  and  in  such  placers  all  kinds 
of  schemes  have  been  exploited ;  and  it  may  be  set  down 
as  an  axiom  that  all  dry  placer  machines  will  prove 
failures,  unless  gold  is  so  plentiful  it  may  be  sifted  from 
the  dirt,  and  under  the  latter  conditions  a  jo-mesh  sieve 


WORKING   DRY  PLACERS  311 

would  suffice.  There  are  cases  on  record  where  mate- 
rial is  pulverized  to  some  extent  and  tossed.  When 
thrown  up  the  wind  blows  the  lighter  material  away, 
while  the  heavier  material  is  caught  on  a  sheet.  This 
is  again  tossed  until  the  heavier  particles  are  concen- 
trated to  small  bulk  and  the  gold  picked  out,  or  the  con- 
centrates carried  to  a  place  where  water  can  be  obtained. 


pifc 
f  w^- 

JH| 
I 


'! 


-: 


FIG.  90. 


The  Allis-Chalmers  Company  exploit  the  Wood  dry 
placer  machine,  but  the  writer  not  being  particularly 
interested  in  that  kind  of  mining  has  never  inquired 
into  its  virtues  or  where  it  has  been  successfully  used, 
unless  the  machine  illustrated  in  Fig.  90,  a  description 


312  TRACTION   DREDGES 

of  which  is  kindly  furnished  us  by  George  W.  Parker, 
represents  that  machine. 

In  the  Engineering  and  Mining  Journal,1  1903,  a 
description  of  the  Edison  and  Freid  dry  concentrators 
may  be  found.  Both  machines  depend  upon  gravity 
and  an  air  current  to  separate  the  lighter  material  from 
the  gold. 

The  process  is  to  size  the  material  and  send  the  sizes 
to  separators  adjusted  to  the  size. 

Dry  washing  is  carried  on  at  the  Sunnyside  mine  near 
Round  Mountain,  Nevada. 

An  idea  of  the  work  performed  can  be  derived  from 
Fig.  64.  The  few  large  rocks  are  picked  out  by  hand 
and  the  gravel  thrown  by  shovels  against  a  i-inch  sand 
screen.  The  screened  material  is  shoveled  into  the  dry 
washers.  The  dry  washer  consists  of  a  screen  with  J- 
inch  openings,  from  which  the  oversize  is  delivered  by 
a  piece  of  sheet  iron  2  feet  beyond  the  end  of  the  machine. 
The  undersize  returns  to  the  head  end,  where  it  is  fed 
on  a  frame  covered  with  a  coarse  heavy  cloth,  across 
which  are  riffles  about  4  inches  apart.  The  frame 
with  riffles  is  shown  in  the  foreground  to  the  right,  and 
the  washer  is  directly  back  of  the  man  cleaning  the 
riffles.  The  frame  when  in  place  forms  the  upper  side 
of  a  bellows  that  is  turned  by  a  crank  having  a  flywheel. 
The  puffs  of  air  through  the  cloth  agitate  the  gravel, 
and,  aided  by  the  slope  of  the  frame,  it  is  discharged 
at  the  lower  end,  while  the  heavier  gold  is  retained  in 
the  riffles.  The  gravel  and  gold  retained  by  the  riffles 
are  brushed  off  into  a  tub,  and  after  a  sufficient  quantity 

1  Mr.  George  W.  Packard,  Mining  Engineer,  Boston,  Massachusetts. 


DRY  WASHING  313 

of  this  concentrate  has  accumulated,  it  is  put  over 
the  machine  a  second  time.  The  tailing  from  this 
second  concentration  contains  gold  and  is  sacked  for 
shipment.  The  concentrate  from  the  second  operation 
is  washed  in  an  ordinary  gold  pan,  and  the  black  iron 
sands  and  gold  separated  by  a  magnet.  Two  machines 
working  loj  hours  per  day,  handle  35  tons  of  dirt.  It 
requires  20  men  to  dig  this  amount  of  dirt,  screen  and 
put  it  through  the  dry  washers.  ,/..  •" 


' ...  K    v   "!.->•'     ','.  •  '   ,    <••>    1   1'- 

:.''.•     <      :'.  !.'•'''       .:.'•         '•  I  •       ..      •  '•'     '•'•  •    •       '•• 


CHAPTER  XH. 

BLACK    SANDS. 

NEARLY  eve.ry  placer  deposit  contains  more  or  less 
magnetite,  meccanite,  or  ilmenite,  and  at  times  other 
heavy  minerals  such  as  garnets,  platinum,  and  the 
platinum  metals,  monozite,  etc.  The  origin  of  the 
sands  is  not  difficult  to  fathom,  for  some  of  them  are 
found  in  the  tailings  from  stamp  mills,  which  indicates 
that  they  were  originally  associated  with  other  minerals 
in  rock  formations.  Minerals  of  this  description  are 
not  easily  oxidized,  and  in  some  cases  are  not  affected 
by  weak  mineral  solutions,  or  acids.  Black  sands  in 
some  cases  are  so  abundant,  that  they  interfere  with 
sluicing  operations,  particularly  in  some  river  opera- 
tions. In  most  instances  they  carry  gold,  which  varies 
from  J  to  90  ounces  per  ton  of  clean  sands.  The  latter 
quantity  is  not  usual,  however,  but  as  high  as  4  ounces 
per  ton  is  not  unusual. 

The  Minister  of  Mines  of  British  Columbia  publishes 
in  his  1904  Report  the  value  of  some  of  the  black  sands 
in  one  sample  at  least  from  the  Caribou  District.  The 
assay  value  was  as  follows: 

Gold,  95  ozs.  per  ton.  Value  $1900  per  ton. 

.Silver,  180    "       "      "          "          90  "      " 

Platinum,        64     "       "      "          "        832  "       " 

314 


PLACER  SANDS  315 

Palladium,    61.4  ozs.  per  ton.  Value  $1769  per  ton 
Osmiridium,    42    "      "     "          "       1386     "     " 

The  remarkable  feature  about  this  deposit  is  that 
the  quantity  of  silver  is  far  in  excess  of  the  amount 
usually  found  with  placer  gold;  further,  that  the  assay 
reflected  some  copper  which  was  probably  alloyed  with 
the  silver,  although  it  may  have  been  alloyed  with  the 
platinum. 

The  quantity  of  iron  in  the  sample  was  neglected; 
however,  all  indications  point  to  the  iron  sands  having 
an  attraction  for  gold  when  in  solutions.  The  nature 
of  the  gold  shows  it  to  be  in  a  very  thin  film  about  the 
oxides,  as  if  placed  there  by  solutions,  and  only  sol- 
vents can  separate  the  two.  Cyanide  solutions  are 
quite  effective  in  obtaining  gold  from  black  sands. 

It  will  be  found  that  the  black  sands  on  seashores 
are  not  as  rich  in  gold  as  the  fresh  water  sands  of  inland 
placers. 

While  there  is  no  question  in  regard  to  the  value  of 
some  black  sands  in  placers,  there  is  great  uncertainty 
as  to  their  quantity. 

This  uncertainty  in  placer  mining  is  sometimes 
the  cause  of  cocoa  matting  tables  becoming  quickly 
filled,  but  this  would  suggest  a  means  whereby  they 
could  be  accumulated  as  a  by-product.  Mr.  John  M. 
Nicol1  writes  interestingly  on  this  subject,  and  we 
have  therefore  taken  the  liberty  of  inserting  some  of 
his  ideas,  which  are  pointed. 

"Unfortunately   for   the  interest  of  abstract  science, 

1  Mining  and  Scientific  Press,  Jan.  19,  1907. 


3i6  BLACK  SANDS 

many  other  workers,  like  myself,  are  no  doubt  engineers 
employed  by  large  firms,  who  cannot,  in  justice  to  them- 
selves or  their  employees,  reveal  all  the  knowledge 
that  they  acquire.  There  are,  however,  a  number  of 
points  of  general  interest  open  to  discussion  by  all 
parties,  and  I  take  pleasure  in  calling  attention  to  some 
of  them. 

"  There  is  no  new  discovery  about '  black  sands. J  They 
are  to  be  found  disseminated  throughout  the  sand  and 
gravel —  both  ancient  and  modern  —  of  practically  all 
river,  lake,  and  sea- beach  deposits.  The  various  min- 
erals are  associated  together  by  virtue  of  the  fact  that 
they  are  all  of  high  specific  gravity,  and  also,  that  owing 
to  their  durable  structure,  Nature  has  had  the  oppor- 
tunity of  concentrating  them  in  the  river  channels  from 
a  vast  area  of  country  from  which  they  were  originally 
eroded,  and  the  nature  of  the  minerals  composing  the 
grains  will  therefore  largely  depend  upon  the  geological 
features  of  this  area.  The  grains  are  of  all  sizes,  from 
a  maximum  of  about  J  in.  diameter  down  to  material 
that  will  pass  through  a  2OO-mesh  screen  or  even  finer. 
"  The  whole  question  is  simply  one  of  ordinary  placer 
mining,  with  some  definite  system  worked  out  for  saving 
a  larger  percentage  of  fine  gold  and  also  of  saving  all  of 
the  other  by-products  that  have  hitherto  been  allowed  to 
run  to  waste,  and  of  doing  this  on  a  strictly  commercial 
basis,  without  undue  capital  expenditure  and  at  such  low 
cost  of  operation  that  a  sufficient  profit  will  result  to 
repay  capital,  interest,  and  a  good  surplus  besides, 
before  the  deposit  is  exhausted. 

"  Wild  statements  have  been  made  regarding  the  value 


BLACK  SAND   POSSIBILITIES  317 

of  black  sands,  and  samples  have  been  submitted  which 
assayed  $i,coo  per  ton,  but  it  must  be  remembered  that 
these  samples  consisted  of  a  few  pounds  actual  weight 
containing  a  few  dollars  actual  value,  that  had  been  con- 
centrated down  from  possibly  many  hundred  cubic 
yards  of  gravel,  and  that  before  one  ton  could  be  obtained 
probably  4,000  to  5,000  tons  of  gravel  had  to  be  washed 
down,  so  that  the  real  value  of  the  original  deposit  in 
place  possibly  did  not  exceed  20  cents  per  ton.  The 
first  thing  to  be  done,  therefore,  is  to  base  all  reports  on 
the  value  per  original  ton  or  cubic  yard  of  gravel  in 
place,  from  which  the  black  sand  concentrate  has  been 
obtained. 

"  In  river  deposits,  the  possible  flood  line  is  of  great 
importance.  Possible  hydro-electric  power  sites  in  the 
neighborhood  should  also  be  noted,  as  there  are  many 
modern  methods  applicable,  that  were  not  within  reach 
of  the  early  placer  miners,  where  electric  power  can  be 
obtained  conveniently  for  pumping,  elevating,  and  con- 
veying, and  for  driving  the  necessary  machinery  for  any 
plant  that  may  be  installed. 

"  The  ground  should  be  thoroughly  tested  either  by 
drilling  or  by  shafts;  if  the  seepage  is  not  excessive,  the 
latter  is  preferable.  In  case  of  an  elevator  proposition, 
the  proportion  of  fine  to  coarse  gravel  must  be  carefully 
noted  as  follows  : 

"  The  proportion  by  volume  per  cubic  yard  of  all  gravel 
below  2  inches,  from  2  to  5  inches  and  from  5  to  12  inches. 
Gravel  over  12  inches  must  be  considered  as  too  large 
either  for  practical  dredging  or  for  hydraulic  elevating. 

"  If  conditions  permit,  the  whole  of  the  gravel -extracted 


3i8  BLACK  SANDS 

should  be  washed,  and  the  coarse  gravel  stacked  on  one 
side.  This  may  be  conveniently  done  by  means  of  a 
washing  platform  discharging  by  a  short  sluice  into  two 
or  more  pairs  of  rockers,  which  may  alternately  be  cleaned 
up  at  short  intervals.  No  riffles  should  be  put  in  the 
sluice,  nor  quicksilver  used.  The  clean-up  of  the 
rocker  riffles  must  be  passed  through  a  lo-mesh  screen, 
the  undersize  going  directly  to  a  settling  vat  for  further 
test  treatment,  and  the  oversize  being  roughly  picked 
over  and  thrown  to  waste.  Any  coarse  nuggets  or  gold 
that  may  be  caught  on  the  rocker  grizzlies  or  on  the 
washing  platform  should  be  kept  separate  and  their 
individual  weights  and  measurements  recorded. 

"  That  which  is  saved  in  the  riffles  of  the  rocker  may  be 
considered  as  material  that  could  be  saved  by  ordinary 
sluice-box  methods  and  that  could  certainly  be  saved  by 
sizing  and  concentrating  on  the  tables.  The  tailing  from 
the  rockers  must  also  be  weighed  and  passed  through  a 
lo-mesh  screen.  The  oversize  should  be  roughly 
picked  over  and  then  thrown  to  waste,  and  the  under- 
size 'panned  down'  by  panning  back  and  forth  between 
two  miner's  pans.  If  skill  and  care  are  exercised, 
practically  all  of  the  black  sand  that  has  escaped  the 
rockers  can  be  saved  by  this  method.  All  of  the  concen- 
trate caught  by  this  means,  will  have  to  be  tested  as 
mentioned  below. 

"  The  gravels  of  different  mines  vary  so  greatly,  as  do 
also  the  proportions  of  the  different  associated  minerals 
and  the  size  of  the  grains,  that  it  is  more  than  probable 
that  each  particular  plant  will  have  to  be  designed  with 
regard  to  the  local  conditions.  I  think,  however,  it 


DRYING  SANDS  319 

will  be  generally  conceded,  that  all  gold  and  platinum 
grains  above  f  inch  diameter  are  comparatively  easy  to 
save.  The  real  question  is  how  to  save  the  fine,  and 
especially  how  to  separate  as  well  as  save  the  associated 
by-products,  without  destroying  one  to  save  the  other. 
The  following  additional  tests  are  therefore  necessary, 
and  will  aid  in  throwing  some  light  on  a  possible  solu- 
tion of  this  problem. 

"The  material  saved  from  the  settling  vat  of  the  rockers, 
and  from  the  pan  concentrate,  should  be  carefully  dried 
in  sheet-iron  trays  over  a  roughly  constructed  furnace. 
For  small  tests,  the  miner's,  gold  pan  may  be  used  for 
this  purpose.  Care  should  be  taken  to  make  certain 
that  the  settling  vats  are  thoroughly  clean,  and  also  that 
the  trays  are  carefully  dusted  after  the  product  has  been 
dried,  as  otherwise  some  of  the  fine  gold  is  liable  to  be 
lost.  The  dried  product  should  now  be  weighed  in 
bulk  and  a  record  made  of  its  actual  weight  in  pounds 
and  of  its  proportionate  weight  per  cubic  yard  of  gravel 
from  which  the  concentrate  was  extracted.  For  small 
hand  tests,  it  is  most  convenient  to  give  the  weight  in 
grams,  and  for  the  large  tests  in  pounds,  though  if  the 
facilities  exist,  it  is  far  best  to  use  the  metric  system 
right  through.  Unfortunately  most  miners  do  not 
understand  the  metric  system,  and  a  report  to  be 
intelligible  to  them,  must  be  given  in  cents  per  cubic 
yard,  and  the  weights  in  pounds. 

"  The  dry  product  should  now  be  passed  through  a 
series  of  ordinary  laboratory  sieves  from  10  down  to 
100  mesh  or  even  finer.  Each  oversize  will  be  carefully 
separated  and  weighed  in  bulk,  the  magnetizable  prod- 


320  BLACK  SANDS 

uct  will  be  removed  and  weighed,  and  the  residue  can 
then  be  conveniently  treated  by  the  old-time  method  of 
blowing,  care  being  taken  to  blow  the  tailing  on  a  large 
sheet  of  paper,  so  that  it  can  be  collected  for  further 
treatment.  The  gold  particles  remaining  in  the  small 
blower  must  then  be  weighed  on  a  button  balance  and 
placed  in  a  small  vial  properly  labeled  for  future  refer- 
ence. An  assay  sample  should  be  taken  from  the  origi- 
nal pan  concentrate  and  also  from  the  magnetizable 
product  and  the  residue  after  the  gold  grains  have  been 
removed,  and  assays  made  and  recorded.  This  process 
may  be  carried  on  for  the  oversize  of  all  the  different 
screens,  and  the  final  undersize,  which  passes  the  finest 
screen,  used.  The  results  of  these  tests  may  then  be 
tabulated. 

"As  the  result  of  these  tests,  it  will  now  be  possible  to 
form  some  idea  as  to  where  the  values  exist,  that  is,  so 
far  as  the  gold  is  concerned,  but  it  will  be  found  to  be 
exceedingly  difficult  to  remove  the  gold  from  the  plat- 
inum, except, by  resorting  to  the  usual  refinery  methods. 
The  residue  remaining  after  removing  the  magnetizable 
product,  will  consist  of  other  by-products,  some  of  which 
may  have  a  commercial  value,  together  with  a  certain 
amount  of  fine  gold,  and  just  here  is  where  the  great 
field  for  research  is  open;  for  at  the  present  moment, 
I  do  not  i  know  any  process  by  which  these  different 
products  may  be  separated  and  put  into  marketable 
forrnv  •** 

"  Care  must  also  be  exercised  in  making  a  magnetic 
separation  of  the  magnetizable  particles,  for  if  too  strong 
a  magnet  is  used  and  swept  hurriedly  through  a  large 


MAGNETIC  SEPARATION  321 

mass  of  sand,  the  clusters  of  iron  grains  will  almost 
always  pick  up  and  hold  in  suspension  a  certain  number 
of  gold  particles.  For  laboratory  purposes,  I  have  found 
it  most  convenient  to  use  an  ordinary  5  or  6-inch  horse- 
shoe magnet  and  to  cover  the  poles  with  a  fine  cambric 
bag.  I  then  spread  out  the  sand  to  the  thickness  of 
rV  inch  on  a  piece  of  paper,  and  gently  pass  the  covered 
magnet  back  and  forth  over  the  surface,  and  the  mag- 
netizable grains  will  cluster  on  the  outside  of  the  bag. 
The  covered  magnet  with  its  adhering  particles  is  then 
placed  in  a  glass  bowl  and  the  magnet  withdrawn  from 
the  bag  and  the  latter  shaken.  This  operation  should  be 
repeated  until  all  the  magnetizable  product  has  been 
separated  from  the  sample.  The  product  collected 
should  again  be  spread  out  on  a  piece  of  cardboard  and 
gone  over  a  second  time  with  the  magnet;  this  .time, 
however,  the  bag  must  be  drawn  tightly  over  the  poles  of 
the  magnet,  and  the  latter  must  be  tapped  gently  while 
picking  up  the  grains,  so  that  any  non-magnetizable 
gold  or  platinum  particle  will  be  freed  from  the  clusters 
and  fall  back  on  the  cardboard  by  virtue  of  its  specific 
gravity.  The  use  of  a  bag  as  described  above  will  be 
found  to  facilitate  the  operation,  and  is  much  quicker 
than  placing  the  bare  poles  of  the  magnet  against  the 
black  sand. 

"  The  gold  that  has  been  separated  should  be  carefully 
examined  under  a  glass,  and  notes  made  regarding  its 
surface  appearance.  It  will  also  be  a  good  plan  to 
make  an  amalgamation  test  and  find  out  by  weighing 
what  proportion  of  the  gold  will  or  will  not  readily 
amalgamate. 


322  BLACK  SANDS 

"As  a  result  of  these  tests,  we  now  have  the  following 
data: 

"  i.  The  weight  of  fine  products  resulting  per  cubic 
yard  of  gravel  that  will  have  to  be  treated  by  concentra- 
tion, and  we  can  now,  therefore,  estimate  upon  the 
necessary  table  area  per  cubic  yard  of  gravel  to  be 
washed. 

"2.  The  weight  of  black  sand  concentrated  per  cubic 
yard  and  the  approximate  gross  value  per  ton  of  con- 
centrate, and  also  per  cubic  yard  of  gravel. 

"3.  The  proportion  by  weight  of  separation  that  can 
be  made  by  magnetic  methods. 

"  4.  The  values,  if  any,  that  are  in  direct  association 
with  the  iron  grains  and  would  be  lost  by  this  method. 
Gold  and  platinum  assays  should  be  made. 

"  5.  The  values  that  remain  in  the  non-magnetic  resi- 
due subsequent  to  wind  separation  of  the  clean  gold,  and 
that  with  our  present  knowledge  can  only  be  saved  by 
smelting. 

"  6.  The  value  of  the  clean  gold  that  has  been  caught 
by  the  three  processes. 

"7.  The  proportion  of  gold  that  will  amalgamate,  and 
if  the  non-amalgamating  gold  is  coarse  or  fine. 

"8.  The  quantity  of  residue  containing  the  by-products 
that  need  further  treatment. 

"  In  the  foregoing,  I  have  merely  outlined  some  of  the 
most  important  tests,  though  numerous  others  will  no 
doubt  be  made  before  a  final  solution  of  the  problem  can 
be  arrived  at.  We  may,  however,  now  commence  to 
formulate  some  definite  arrangement  for  a  plant  to 
treat  the  black  sand  and  to  indicate  the  nature  of  the 


SCREENING  SANDS  323 

problems  most  likely  to  be  encountered.  Broadly 
speaking,  all  of  the  coarse  material  of  a  placer  is  value- 
less, and  therefore  the  sooner  it  is  dumped  and  gotten 
rid  of,  the  better.  All  coarse  gold  above  J-inch  size 
is  easy  to  catch,  and  an  arrangement  of  a  few  riffles  in 
a  short  line  of  sluices  will  take  care  of  that  feature. 
Hence  the  first  and  most  important  step  is  to  size  the 
material,  say  to  J  inch,  and  reject  the  coarse  after  passing 
through  a  sluice.  It  will  be  equally  necessary  to  get  rid 
of  the  excessive  quantity  of  clay  and  fine  product,  which 
might  impede  the  successful  operation  of  further  con- 
centration. 

"As  dump  is  an  important  consideration  in  many  placer 
mines,  it  will  be  necessary  to  design  a  plant  with  as 
little  loss  of  head  room  as  possible,  and  I  would  suggest 
the  following  arrangement:  At  the  discharge  end  of  a 
sluice,  where  the  material  is  received  from  mining 
operations,  a  grizzly  should  be  placed,  having  a  suffi- 
cient area  to  pass  all  of  the  fine  material  and  practically 
all  of  the  water.  It  should  be  placed  at  such  an  angle 
that  the  coarse  material  will  roll  off  to  dump.  The 
grizzly  should  be  provided  with  taper  bars  and  spaced 
about  i7*  inch.  All  of  the  fine  material  will  pass  by  a 
large  sluice  to  a  distributing  and  hydraulic  classifier, 
which  will  get  rid  of  the  excess  water  and  very  light  sand 
and  clay  held  in  suspension. 

"As  a  certain  amount  of  float  gold  might  be  carried 
away  to  the  reject,  I  would  suggest  that  this  be  passed 
through  some  form  of  amalgamating  device,  —  the  Pierce 
amalgamator  being  a  good  machine  for  this  purpose,  — 
and  as  the  light  gold  has  probably  a  clean  surface,  it 


324  BLACK  SANDS 

will  be  fairly  easy  to  amalgamate.  It  will,  however, 
be  advisable  to  make  a  number  of  tests  by  means  of  set- 
tling vats,  to  find  out  whether  the  value  of  the  gold 
and  by-products  saved  will  be  worth  the  capital  outlay 
necessary  to  save  them. 

"  The  heavy  sand  from  the  hydraulic  classifiers  will 
pass  to  some  form  of  classifying  sieves,  designed  to  handle 
a  large  bulk  at  a  minimum  of  capital  and  current  ex- 
penditure. These  should  size  from  T5^  to,  say,  J  inch, 
and  must  be  of  simple  and  durable  structure,  or  the 
placer  miner  will  never  bother  with  them. 

"  To  size  all  of  the  material  from  a  placer  mine,  to 
reduce  the  product  to  be  treated  to  a  minimum  bulk, 
economically  and  without  loss,  and  to  deliver  it  in  a 
form  suitable  for  further  concentration  and  treatment, 
is  a  matter  that  offers  a  broad  field  for  intelligent  design 
and  invention.  The  quantity  and  proportion  of  this 
sized  product  to  the  original  gravel  will  vary  according 
to  the  nature  of  the  gravel  mined;  and  judging  from  my 
experience,  it  will  be  least  in  modern  river  channels, 
and  greatest  in  deep,  ;  ancient  deposits,  and  may  vary 
from  20  to  60  per  cent  of  the  original  deposit. 

"  Some  form  of  concentration  must  now  be  adopted  to 
treat  the  fine  material,  and  although  cocoa  matting 
tables  with  expanded  metal  riffles  have  been  used  fairly 
successfully  for  the  purpose,  they  are  to  be  condemned 
because  they  are  not  continuous  in  operation;  and  all 
forms  of  non-continuous  concentration  are  bad,  owing 
to  the  fact  that  the  surfaces  choke  and  the  values  com- 
mence to  slide  over  and  are  lost.  This  is  prevented  by 
frequent  clean-ups,  but  this  entails  too-great  an  outlay 


TREATMENT  OF   SANDS  325 

for  current  expenses,  and  quickly  reduces  profits  when 
treating  such  a  low  grade  product  as  the  sand  of  placers. 

"The  Finder  concentrator  is  a  good  machine  for  this 
purpose.  Its  capacity  is  about  40  tons  per  day,  equiva- 
lent to  handling  the  product  from  60  to  100  cubic  yards 
of  gravel.  It  is  also  capable  of  delivering  three  grades 
of  concentrates  and  tailing.  Any  form  of  concentrator 
could  be  adopted,  according  to  the  ideas  of  the  mine 
owner. 

••"The  suggestion  is  made  to  the  miner  to  either  ship 
his  product  to  a  smelter,  or  hire  a  skilled  metallurgist. 
If  he  desires  to  be  his  own  metallurgist,  proceed  as  fol- 
lows: Treat  with  diluted  nitric  acid;  wash;  amalgamate 
without  grinding,  to  remove  the  free  gold;  wash  residue 
through  a  fine  steel-wire  sieve.  If  platinum  is  present, 
this  can  be  dissolved  by  acids,  using  about  15  times  its 
weight  of  aqua  regia,  and  precipitate  by  sal  ammoniac. 
The  precipitate  of  platm-ammonium  chloride  can  be 
dried  and  treated  by  the  usual  refining  methods." 

Dr.  David  Day  of  the  United  States  Geological  Sur- 
vey had  charge  of  an  experimental  station  at  the  Lewis 
and  Clark  -Exposition,  the  object  of  which  was  to  con- 
centrate black  sands,  and  extract  therefrom  the  valu- 
able minerals.  The  method  he  followed  was  about  as 
follows:  First  the  sand  was  dried,  and  the  magnetic 
minerals  separated  by  magnetic  concentration;  the  sands 
were  then  converted  into  pig  iron  and  steel  by  the  elec- 
tric furnace. 

The  tailing  .contained  the  gold  that  was  not  lost  by 
magnetic  concentration,  platinum  and  other  non-mag- 
netic sands. 


326  BLACK  SANDS 

From  a  commercial  standpoint  the  process  was  not 
a  success,  although  it  was  talked  about  freely,  and 
some  unskilled  in  mining  presumed  it  was  a  wonder- 
ful discovery  of  science.  To  spend  $5  to  recover  $i  is 
not  a  scientific  discovery,  and  the  whole  affair  was  the 
cause  of  much  amusement  to  mining  engineers  and 
metallurgists. 

On  this  subject  .the  Chicago  Inter-Ocean  said: 

Dr.  Day  has  demonstrated  to  the  people  of  the  Pacific  coast 
that  values  of  untold  billions  of  dollars  are  to  be  found  in  the  black 
sands  which  line  almost  the  whole  Pacific  coast  and  form  the  banks 
and  river  bottoms  of  almost  every  river  flowing  into  the  Pacific 
Ocean,  from  Alaska  to  Southern  California. 

That  these  black  sands  contain  a  large  percentage  of  iron  has 
been  known  for  many  years.  In  fact,  it  has  been  estimated  that, 
if  the  iron  could  be  separated  from  the  sand  and  smelted,  the 
Pacific  coast  could  supply  sufficient  iron  for  the  markets  of  the  world 
for  thousands  of  years,  but  as  yet  no  practical  method  has  been 
discovered  for  separating  the  iron  in  commercial  quantities  from 
the  sand. 

Machines  have  been  made  which  will  separate  the  iron  from 
the  sand  in  small  quantities  when  the  sand  has  been  thoroughly 
dried,  but  the  capacity  of  these  machines  is  so  limited,  and  the  cost 
of  drying  the  sand  is  so  great,  as  to  render  them  commercially  value- 
less for  treating  the  black  sands. 

STOREHOUSE    OF    RARE    MINERALS. 

But  Dr.  Day  demonstrated  at  the  exposition  at  Portland  that 
the  black  sand  of  the  Pacific  coast  contains  many  other  valuable 
minerals.  Professor  Richards,  of  the  Boston  School  of  Technology; 
Professor  Kemp,  of  Columbia  College;  J.  F.  Batchelder,  chairman 
of  the  mining  committee  of  the  Portland  Board  of  Trade;  and  an 
able  corps  of  assistants  from  the  various  schools  of  technology,  all 


DR.   DAY'S  EXPERIMENTS  327 

under  the  supervision  of  Dr.  Day,  carried  on  an  exhaustive  analysis 
of  the  black  sands,  from  samples  taken  from  thousands  of  loca- 
tions along  the  beaches  of  the  Pacific  coast,  the  beds  and  bars  of 
rivers  flowing  into  the  Pacific  Ocean,  as  well  as  from  the  dry  beds 
of  ancient  rivers  in  the  interior  of  the  Western  country. 

The  preliminary  reports  of  Dr.  Day's  investigations  have  already 
been  published  by  the  government  at  Washington,  and  the  publi- 
cation of  his  complete  report  is  eagerly  looked  for  by  the  people 
of  the  Pacific  coast. 

While  it  was  known  that  the  black  sands  contained  free  gold  in 
varying  quantities,  yet  it  was  considered  impossible  to  .recover  this 
gold,  on  account  of  its  being  mixed  with  the  heavy  grains  of  iron, 
and  no  practical  way  of  freeing  it  from  the  iron  being  known.  How- 
ever, the  government  reports  of  Dr.  Day's  experiments  show  that, 
after  he  dried  the  black  sand  and  extracted  the  iron,  by  using  one 
of  the  machines  already  referred  to,  it  was  possible  to  recover  the 
free  gold  in  paying  quantities. 

GOLD  FROM  THE  IRON. 

But  this  is  not  all.  The  reports  show  that  nearly  all  the  iron  in 
the  black  sands  carries  "rusty"  gold  and  that,  by  separating  the 
iron  grains  from  the  sand  and  treating  the  iron  itself,  values  in  gold 
were  obtained  running  from  $6  to  $600  per  ton  of  iron  extracted. 
Furthermore,  by  placing  the  sand  (from  which  the  heavy  iron  had 
been  extracted)  on  the  gently  oscillating  tables,  where  the  separa- 
tion of  the  sand  into  its  component  parts  was  made  by  gravity  by 
pouring  water  over  the  incline,  it  was  discovered  that  the  sand 
contained,  besides  gold,  large  quantities  of  other  valuable  minerals 
which  were  easily  separated,  such  as  monazite  chromite,  garnet, 
zircon,  etc.  (some  of  them  worth  over  $400  per  ton,  and  platinum, 
which  is  more  valuable  even  than  gold. 

As  if  these  discoveries  of  untold  values  were  not  sufficient  to  set 
the  mining  world  of  the  West  on  fire  with  excitement  and  antici- 
pation, Dr.  Day,  after  demonstrating  that  many  of  the  sands  tested 
contained  as  high  as  600  pounds  of  iron  to  the  ton,  erected  a  ten- 


328  BLACK  SANDS 

ton  electric  furnace,  and  in  one  shdrt  hour,  by  adding  lime  and 
broken  coal  to  the  iron,  which  had  been  separated  from  the  black 
sands,  smelted  the  iron  into  high  grade  steel,  which  has  stood  all 
tests  for  purity  and  toughness,  and  shown  that  the  black  sands  of 
the  Pacif.c  coast  will  stand  alongside  Norwegian  and  Swedish  iron 
ore  as  the  mother  of  steel. 

$100,000,000  IN  IRON. 

The  discovery  has  created  even  greater  interest  than  the  fact 
that  the  sands  contain  gold  and  platinum  and  other  precious  miner- 
als, for  the  Pacific  coast  States  and  Territories  always  have  depended 
on  the  East  for  their  supplies  of  steel  and  iron.  The  steel  business 
of  the  Pacific  coast  amounts  to  more  than  $100,006,000  per  year, 
and  oh  every  tdn  of  iron  or  steel  used  on  the  Pacific  coast,  a  cost  of 
$16  ]£fef  toft  has  to  be  added  for  freight  charges,  the  freight  being 
regulated^D/the rates^by  water;  fdr  so' difficult  is  it  to  get  sufficient 
iron  to  the  Pacific  coast  to  supply  its  rapidly  increasing  demand 
for  the  material,  that  thousands  upon  thousands  of  tons  of  iron  and 
steel  are  b roughti  around  tyy  Cape  Horn  by  boat  from  Glasgow, 
Scotland.  This  is  taking  coals  to  Newcastle  with  a  vengeance, 
^foEiin)  almost  every  foot  of  sand  lapped  by  the  waters  of  the  Pacific 
jQce,an^  along  the  shores  of  the  States  of  the  West,  is  found  the  pre- 
idous  iron  which  the  people  of  the  West  now  go  thousands  of  miles 
from  home  to  purchase.  .'.:,..;..> 

j  ,  The  questions  of  interest. that  naturally  arise  are: 
...  i.  How  did  these  minerals  get  into  the  sand?  •>  i  , . ,.*' 

2.  How  extensive  are  the  sand  beds?  •;  •  .: 

3.  What  percentage  of  iron  does  the  sand  contain  per  ton  ?        i.  •. 

4.  How  are  the  iron  and  minerals  to  be  extracted  in  commercial 
quantities? 

CONTAINS   INCONCEIVABLE   WEALTH. 

Dr.  Day's  investigations,  for  which  special  purpose  the  last  Con- 
gress made  a  liberal  appropriation,  show  that  the  black  sand  is 
found  in:  enormous,  unlimited  deposits  along  the  ocean  beaches 


BLACK  SAND  FORMATION  329 

of  the  Pacific  States,  but  particularly  along  the  coast  of  Oregon. 
In  some  cases  the  sands  of  these  beaches  have  been  found  to  con- 
tain as  high  as  40  per  cent  of  iron. 

But  the  greatest  values  per  ton  of  sand  are  found  in  the  beds 
of  the  rivers  flowing  into  the  ocean,  for,  while  they  contain  less 
iron  (in  some  cases  as  low  as  10  per  cent),  still  their  values  run 
higher  in  gold  and  other  precious  minerals,  for  these  sands  are 
formed  by  erosion  and  the  breaking  down  of  eruptive  rocks  which 
contain  minerals  and  metals  of  most  diverse  kind  and  value  in  their 
structure.  The  dissolution  of  these  mineral  rocks  along  the  course 
of  the  various  rivers  for  ages  past  and  the  erosion  caused  by  these 
rivers,  which  have  been  cutting  channels  through  these  rocks  for 
probably  hundreds  of  thousands  of  years,  have  separated  the  rocks 
into  their  component  parts,  forming  the  black  sand,  and  the  rivers, 
even  now,  are  ceaselessly  carrying  this  precious  sand  down  their 
entire  course  and  dumping  it  into  the  Pacific  Ocean,  where,  by  dif- 
ferent currents,  it  is  returned  to  the  mainland  to  build  up  the  black 
sand  beaches  of  the  Pacific  coast. 


ERODED   ROCK   RELEASES   GOLD. 

The  pieces  of  eroded  rock  from  constant  friction  one  upon  the 
other,  during  their  course  down  the  river,  gradually  grow  smaller 
and  smaller  as  they  are  moved  farther  down  the  liver  by  its  currents, 
gradually  dropping  their  burden  of  precious  minerals,  until,  on 
reaching  the  ocean,  the  sand  contains  more  iron  than  anything 
else,  while  the  higher  values  in  gold  have  been  left  farther  up  the 
river,  where  they  are  found  in  such  large  quantities,  unmingled 
with  a  high  percentage  of  iron,  that  placer  dredging  has  become 
an  established,  lucrative  business  pursuit. 

The  black  sand  has  always  been  known  as  the  "thief"  of  the 
placer  miner,  for  sand  or  gravel  that  runs  higher  than  2  per  cent  in 
iron  cannot  be  worked  profitably  by  methods  now  in  vogue,  for 
the  grains  of  iron,  being  nearly  as  heavy  as  gold,  fill  up  the  riffles 
and  make  the  separation  of  gold  impossible.  In  fact,  many  of  the 
most  valuable  placer  mines  are  idle  to-day  on  account  of  the  black 


330  BLACK  SANDS 

sand  thief,  which  the  United  States  Government  now  tells  us  con- 
tains, in  itself,  more  wealth  than  human  mind  can  conceive. 
Summing  up  we  find 

1.  That   the  aggregate   amount  of  magnetic  iron   contained  in 
the  black  sands  of  the  Pacific  slope  is  beyond  calculation  and  prac- 
tically inexhaustible,  as  the  deposits  are  being  constantly  added  to 
by  natural  accretion. 

2.  That,  in  order  to  utilize  this  iron  commercially,  it  must  first 
be  magnetically  separated  from  the  sand,  without  drying,  as  the 
cost  of  drying  a  ton  of  sand  for  the  purpose  of  recovering  40  to  400 
pounds  of  iron  is  much  greater  than  the  commercial  value  of  the 
product  warrants. 

3.  That,  with  the  iron  extracted,  the  high  class  minerals,  such 
as  gold,  platinum,  monazite,  zircon,  etc.,  which  are  almost  uni- 
versally found  in  these  sands,  can  be  easily  and  cheaply  separated 
from  the  surrounding  "gangue"  by  methods  of  concentration  now 
in  general  practical  use. 

4.  That  the  magnetic  iron  itself  almost  always  contains  sufficient 
"rusty"  gold  to  yield  a  handsome  profit  by  lixiviation,  although, 
as  a  rule,  not  enough  to  pay  for  treatment  by  any  other  process 
now  known. 

5.  That  the  magnetic  iron  when  separated  from  the  sand  can  be 
reduced  in  an  electric  smelter  to  commercial  iron  or  steel,  ready  to 
supply  the  Pacific  coast  markets. 

6.  That  the  steel  so  produced,   smelted  with  cheap  electricity 
generated  from  water  power,  need  not  exceed  $12  per  ton,  while 
the  present  cost  of  pig  iron  on  the  Pacific  coast  is  over  $27  per  ton  — 
a  saving  of  $15  per  ton  over  present  prices  of  pig  iron  alone. 

The  government  has  pointed  the  way  to  fabulous  fortunes  and 
gigantic  commercial  enterprises  through  the  black  sands.  It  now 
remains  to  be  seen  if  scientific  discovery  and  further  experiment 
will  lead  the  way  to  the  practical,  profitable,  commercial  uses  of 
the  limitless  black  sand  beds  of  our  Western  empire. 

That  this  article  tells  the  situation  exactly,  is  evident 
from  the  following  copy  of  a  letter  written  by  Dr.  Day 


LOVETT  CONCENTRATOR  331 

himself  to  the  manager  of  the  Inter-Ocean  Newspaper 
Company. 

DEPARTMENT  OF  THE  INTERIOR: 

UNITED  STATES  GEOLOGICAL  SURVEY. 

PORTLAND,  ORE.,  February  21,  1906. 

Mr.   Samuel  S.   Sherman,   Business   Manager,    The  Inter-Ocean, 
Chicago,  III. 

DEAR  MR.  SHERMAN:  I  thank  you  very  much  for  your  very  com- 
plimentary article  of  January  21,  which  requires  but  little  in  order 
to  make  it  perfect. 

I  will  be  glad  to  give  you  further  reports  on  the  black  sand  work. 
Congress  has  just  extended  the  work,  and  it  will  start  again  in  a 
few  days. 

The  black  sand  subject  is  really  one  of  very  great  interest  and 
is  going  to  aid  very  much  good  citizenship  on  the  Pacific  coast,  for 
it  is  not  a  matter  of  speculation  but  simply  of  untiring  industry, 
with  all  the  personal  improvements  of  character  which  come  by  that 
kind  of  work  as  contrasted  with  the  usual  speculation  so  frequent 
in  the  mining  industry.  Yours  very  truly, 

DAVID  T.  DAY. 

The  only  concentrator  we  know  of  in  the  United 
States  that  will  treat  the  black  sands  wet  is  shown  in 
Fig.  91. 

This  machine,  which  is  not  large,  handles  dry  material 
readily,  to  my  satisfaction;  and  Mr.  J.  F.  Batchelder,  who 
was  employed  by  the  Government  in  its  investigation  of 
black  sands,  considers  that  it  preempts  the  whole  field 
opened  by  the  Government's  investigations  at  Portland. 
The  Lovett  system  consists  in  raising  black  sand  from 
a  river  bottom  by  means  of  a  pneumatic  device  or  other 
means.  The  material  so  raised  is  screened,  and  the  fine 


332 


BLACE.  SANDS 


material  carried  to  a  sluice  box  in  which  is  placed  a  Lovett 
magnetic  separator.  The  tailing  is  passed  to  mercury 
plates.  The  claim  is  then  made  that  "  this  process  of 


FIG.  91. 

recovering  free  gold  is  protected  by  United  States  patent, 
which  covers  the  use  of  any  solvent  after  magnetic  sepa- 
ration." The  writer  ten  years  ago  made  experiments  on 
concentrates  with  cyanide  solutions,  the  concentrates 
having  been  extracted  from  a  mass  of  sand  by  means  of 
a  magnet.  We  therefore  think  this  claim  somewhat 
broad,  and  the  writer  believes  that  Professor  Christy 
also  made  experiments  of  this  kind  in  the  University  of 
California. 


CHAPTER  XIII. 

UNITED  STATES  MINE  LAWS. 

THE  subject  of  placer  mines  brings  up  the  question, 
How  can  they  be  obtained?  If  one  has  to  purchase 
them,  the  demand  will  not  be  great;  if  one  can  locate  a 
claim,  the  subject  becomes  interesting  to  the  majority  of 
gold  seekers.  Information  upon  this  subject,  which  is 
well  known  in  the  mining  States  of  the  West,  is  entirely 
unknown  in  the  East,  except  by  those  who  make  a  busi- 
ness of  mining. 

Prior  to  the  Congressional  Act  of  1866  the  ownership 
of  mineral  lands  was  retained  by  the  Government.  The 
agitation  for  the  sale  of  such  lands  began  in  1850,  the 
object  being  to  make  them  a  source  of  revenue.  The 
wise  policy  of  leaving  such  lands  open  for  private  devel- 
opment prevailed  until  1866,  when  the  uncertainty  of  titles 
demanded  a  change.  Possessory  rights  were  all  that 
could  be  conferred  on  mining  claims,  and  this  could  be 
retained  by  working  and  the  payment  of  a  small  royalty. 
The  law  was  merely  a  license  to  citizens  of  the  United 
States  to  .go  upon  mineral  lands  of  the  public.  The 
Government  owned  the  land,  but  placed  no  claim  of 
ownership  on  minerals  extracted,  except  so  far  as  license 
fees  or  royalty  was  concerned. 

The  Act  of  May  10,  1872,  allowed  any  person  a  citizen, 
or  one  who  had  declared  his  intentions  to  become  such, 

333 


334  UNITED  STATES  MINE   LAWS 

and  no  others,  to  locate  and  hold  a  mining  claim  1500 
feet  long  by  600  feet  wide,  the  claim  to  be  by  one  person, 
1500  linear  feet  along  the  course  of  the  mineral  vein  or 
lode,  subject  to  location;  or  any  association  of  persons, 
severally  qualified  as  above,  may  make  joint  location  of 
such  claim  of  1500  feet;  but  in  no  event  could  a  location 
of  a  vein  or  lode,  made  subsequent  to  the  date  mentioned, 
exceed  1500  feet  along  the  course  thereof,  whatever 
should  be  the  number  of  persons  in  the  company.  With 
regard  to  the  extent  of  surface  ground  adjoining  a  lode  or 
vein,  and  claimed  for  the  convenient  working  of  the  same, 
it  is  provided  that  the  lateral  extent  of  location,  made 
after  May  10,  1872,  shall  in  no  case  exceed  300  feet  on 
each  side  of' the  middle  of  the  vein  at  the  surface,  and 
that  no  surface  rights  shall  be  limited  by  any  mining 
regulations  to  less  than  25  feet  on  each  side  of  the  middle 
of  the  vein  at  the  surface,  except  where  adverse  rights, 
existing  on  the  loth  of  May,  1872,  may  render  such 
limitations  necessary;  the  end  lines  of  such  claims  to  be 
in  all  cases  parallel  with  each  other. 

Thus  it  may  be  seen  that  no  lode  claim,  located  after 
May  10,  1872,  can  exceed  a  parallelogram  1500  by  600 
feet,  but  whether  surface  ground  of  that  width  can  be 
taken  depends  upon  the  local  or  State  laws  in  force  in 
the  mining  district;  but  no  such  laws  shall  limit  a  vein 
or  lode  claim  to  less  than  1500  feet  along  its  course,  nor 
can  surface  rights  be  limited  to  less  than  50  feet  in  width, 
unless  adverse  claims,  existing  on  May  10,  1872,  render 
such  lateral  limitations  necessary.  It  is  provided  by  the 
Revised  Statutes  that  miners  of  each  district  may  make 
such  rules  and  regulations  not  in  conflict  with  the  laws 


ASSESSMENT  WORK  335 

of  the  United  States,  or  of  the  State  or  Territory  in  which 
the  districts  are  situated,  governing  the  location,  manner 
of  recording,  and  amount  of  work  necessary  to  hold  pos- 
session of  a  claim.  In  order  to  hold  a  possessory  right 
to  a  location  made  prior  to  May  10,  1872,  not  less  than 
$100  worth  of  labor  must  be  performed  or  improvements 
made  thereon  within  one  year  from  the  date  of  such  loca- 
tion, and  annually  thereafter;  in  default  of  which  the 
claim  will  be  subject  to  relocation  by  any  one  else  having 
the  necessary  qualifications,  unless  the  original  locator, 
his  heirs,  assigns,  or  legal  representatives  have  resumed 
work  after  such  failure  and  before  relocation.  The 
expenditures  required  upon  such  claims  may  be  made 
from  the  surface,  or  in  running  a  tunnel  for  their  devel- 
opment. The  Act  of  February  n,  1875,  provided  that 
where  a  person  or  company  has  run  a  tunnel  for  the  pur- 
pose of  developing  a  lode  or  lodes  the  money  so  expended 
shall  be  considered  as  expended  on  the  said  lodes,  and 
the  owners  shall  not  be  required  to  perform  work  on  the 
surface  to  hold  the  claim.  California  has  recently  passed 
a  new  local  mining  law  which  in  some  respects  is  better 
than  the  former  law,  but  in  others  falls  short  of  what  is 
necessary.  The  two  most  needed  matters  in  such  State 
laws  are: 

What  shall  constitute  a  proper  marking  of  a  claim  so 
as  to  avoid  litigation?  The  locator  of  a  claim  should 
therefore  not  neglect  his  corner  pillars,  and  make  them  as 
conspicuous  and  durable  as  possible. 

The  other  matter  referred  to  is,  What  amount  of 
assessment  work  shall  be  done  to  hold  claims,  and  pre- 
vent persons  from  evading  the  spirit  of  the  United  States 


336  UNITED   STATES  MINE  JAWS 

statute  in  regard  to  assessment  work?  The  locator  of 
a  claim  should  familiarize  himself  with  the  local  laws  of 
the  State  or  Territory  in  which  he  lays  out  his  claim ;  other- 
wise it  may  be  "jumped,"  i.e.,  have  some  one  take  it 
away  from  him. 

Individual  proof  of  citizenship  may  be  made  by  affida- 
vit :  if  a  company  unincorporated,  by  the  agent's  affidavit ; 
if  a  corporation,  by  filing  a  copy  of  the  charter  or  certifi- 
cate of  incorporation  with  the  secretary  of  state,  county 
recorder,  or  with  the  nearest  government  land  officer  — 
possibly  better  with  each. 

Locators  against  whom  no  adverse  rights  rested  on 
the  date  of  the  Act  of  1872  shall  have,  on  compliance 
with  general  and  recognized  custom,  the  exclusive  right 
to  possession  and  enjoyment  of  the  surface  inclosure 
and  of  "all  veins,  lodes,  and  ledges  which  lie  under  the 
top  or  apex  of  such  lines,  extended  downwards  verti- 
cally, even  though  they  in  their  descent  extend  outside 
the  side  lines  of  such  surface  locations."  (Probably  the 
best  expert  on  the  Apex  Law  is  Dr.  Rossiter  W.  Ray- 
mond,1 of  New  York  City.  He  is  one  of  the  framers  of 
the  law  of  1875,  and  because  of  his  being  at  one  time  at 
the  head  of  the  U.  S.  Government  Survey,  he  is  con- 
sidered to  be  the  best-informed  man  on  the  subject.) 
The  right  to  such  outside  parts  of  veins  or  ledge  is  con- 
fined to  all  that  lies  between  "vertical  planes  drawn 
downward,"  as  described,  so  continued  that  these  planes 
"will  intersect  the  exterior  parts  of  the  said  veins  or 
ledges."  The  surface  of  another  claim  cannot  be 
entered  by  the  locator  or  possessor  of  such  lode  or  vein. 

1   Law  of  the  Apex.     R.  W.  Raymond.     A.  I.  M.  E.  Transactions. 


RAILROAD  PATENTS  337 

The  land  office  construes  the  word  deposit  to  be  a 
general  term,  embracing  lodes,  ledges,  placers,  and  all 
other  forms  in  which  valuable  metals  have  been  dis- 
covered. Whatever  is  recognized  as  mineral  by  stand- 
ard authorities,  where  the  same  is  found  in  quality  and 
quantity  sufficient  to  render  land  sought  to  be  patented 
more  valuable  on  this  account  than  for  the  purposes  of 
agriculture,  is  treated  by  the  land  office  as  coming  within 
the  meaning  of  the  act.  Lands,  therefore,  valuable  on 
account  of  borax,  sodium  carbonate,  nitrate  of  soda, 
alum,  sulphur,  petroleum,  and  asphalt  may  be  patented. 

The  first  section  of  the  Act  of  1872  says,  "all  valuable 
mineral  deposits."  The  sixth  section  uses  the  term 
"valuable  deposits."  This  latter  section  required  the 
Supreme  Court  to  rule  petroleum  a  mineral  deposit. 
This  session  of  Congress,  December,  1897,  was  presented 
with  a  bill  drafted  by  Mr.  A.  H.  Ricketts,  a  mining  law- 
yer of  San  Francisco,  the  purpose  of  which  was  to  recover 
from  railroad  companies  those  lands  for  which  they 
received  patents  which  lands  were  known  to  be  mineral 
before  the  patents  were  issued,  where  they  have  not 
passed  into  the  hands  of  innocent  purchasers.  Such  a 
bill  is  eminently  proper,  and  would  take  away  from  the 
railroad  companies  only  lands  which  they  ought  never  to 
have  received  and  which  the  California  Miners'  Asso- 
ciation sought  so  strenuously  to  prevent  their  obtaining.1 
"It  is  said  to  be  the  practice  of  the  railroad  companies, 
when  they  receive  patents  for  lands  to  which  they  know 
they  are  not  entitled,  to  transfer  them  to  some  outside 
party  who  claims  to  be  an  innocent  purchaser."  "The 

1   Mining  and  Scientific  Press,  Dec.  18,  1897. 


338  UNITED  STATES  MINE  LAWS 

miners  generally  are  determined  that  the  railroad  com- 
panies shall  not  hold  mining  property  that  never  was 
granted  by  Act  of  Congress." 

The  grant  of  Congress  referred  to  was,  that  certain 
railroads,  because  of  their  being  built,  should  have  each 
alternate  additional  section  for  ten  miles  back  on  each 
side  of  the  roads  as  completed,  but  excludes  all  minerals 
except  iron  and  coal  from  the  grant.  As  fast  as  the  lands 
were  surveyed  the  companies  applied  for  patents. 

Prospectors  cannot  obtain  claims  on  patented  lands, 
and  consequently  should  keep  off  them.  Mr.  Ricketts' 
proposed  law  defines  the  word  mineral  to  mean  "  cinna- 
bar, copper,  lead,  borax,  asphalt,  petroleum,  oil,  salt, 
and  sulphur." 

Deposits  of  fire  clay  may  be  patented  under  the  Act 
of  1872,  and  so  may  iron  ore  deposits  be  patented  as 
vein  or  placer  claims.  Lands  more  valuable  on  account 
of  deposits  of  limestone,  marble,  kaolin,  and  mica  than 
for  purposes  of  agriculture  may  be  patented  as  mineral 
lands. 

The  Act  further  provides  that  no  lode  claim  can  be 
recorded  until  after  the  discovery  of  the  vein  or  lode 
within  the  limits  of  the  ground  claimed.  The  claimant 
should  therefore,  prior  to  recording  his  claim,  unless  he 
can  trace  the  vein  on  the  surface,  sink  a  shaft,  run  a  tun- 
nel or  drift  to  a  sufficient  depth  therein  to  discover  and 
develop  a  mineral  bearing  vein,  lode,  or  crevice;  should 
determine,  if  possible,  the  general  course  of  such  vein  in 
the  direction  from  the  point  of  discovery,  in  which  direc- 
tion he  will  be  governed  in  making  the  boundary  of  his 
claim  on  the  surface;  and  he  should  give  the  course  and 


LOCATING   CLAIMS  339 

direction  as  nearly  as  practicable  from  the  discovery 
shaft  on  the  claim  to  some  permanent  well-known  points 
of  objects,  such  as,  for  instance,  stone  monuments, 
blazed  trees,  the  confluence  of  streams,  etc.,  which  may 
be  in  the  immediate  vicinity,  and  will  serve  to  perpetuate 
and  fix  the  locus  of  the  claim,  and  render  it  susceptible  of 
identification  from  the  description  thereon  given  in  the 
record  of  location  in  the  district.  He  should  drive  a  post 
or  erect  a  monument  of  stones  at  each  corner  of  his  sur- 
face ground,  and  at  the  point  of  discovery  or  discovery 
shaft  should  fix  a  post,  stake,  or  board,  upon  which 
should  be  the  name  given  the  lode,  the  name  of  the  loca- 
tor, the  number  of  feet  claimed,  and  in  what  direction 
from  the  point  of  discovery,  it  being  essential  that  the  loca- 
tion notice  be  filed  for  record.  In  addition  to  the  fore- 
going, the  description  should  state  whether  the  entire 
claim  of  1500  feet  be  taken  on  one  side  of  the  point  of 


POST  POST  P 

O O 


6.W. 


LOCATION  STAKE 

% 

DISCOVERY  SHAFT 


N.E. 


P 

FIG.  92. 


-O 


discovery  or  whether  it  is  partly  upon  the  other  side,  and 
in  the  latter  case  how  many  feet  are  claimed  upon  each  side 
of  such  discovery  point. 

Parties   locating  lodes   are   entitled   to  all   the  dips, 


340  UNITED  STATES  MINE  LAWS 

spurs,  angles,  variations,  and  ledges  of  the  lode  com- 
ing within  the  surface  ground. 

The  following  diagram  will  aid  the  locator  in  his 
work  (Fig.  92): 

MINER'S  FORM  OF  NOTICE. 

I,   John   Doe,   hereby  give  notice   that   I  have  this 

— th  day  of ,  A.D.  18 — ,  located  this,  the 

lode.  I  claim  1500  feet  in  and  along  the  vein,  linear 
and  horizontal  measurement.  I  claim  1200  feet  along 
the  vein  running  in  a  northeasterly  course  from  the 
discovery  shaft,  and  300  feet  running  along  the  vein 
in  a  southwesterly  course  from  the  discovery  shaft. 
I  also  claim  150  feet  on  each  side  of  the  vein  from  center 
of  crevice  as  surface  ground. 

JOHN  DOE,  Locator. 

In  case  there  are  more  than  two  locators,  the  names 
of  the  two  should  be  inserted,  and  the  pronoun  "we" 
where  "  I  "  occurs. 

There  may  be  intervening  claims  which  will  lessen 
the  length  or  the  width  of  the  claim.  Within  reason- 
able time  after  the  location  shall  have  been  marked  on 
the  ground,  notice  thereof  accurately  describing  the 
claim  in  manner  aforesaid  should  be  filed  for  record 
with  the  proper  recorder  of  the  district,  who  will  there- 
upon issue  the  usual  certificate  of  location.  District 
customs  are  followed  in  this  matter,  and  should  be 
familiarized  by  the  prospector.  These  regulations  will 
require  that  a  location  certificate  be  filed  with  the 


RECORDING   LOCATION  341 

recorder,  in  the   county  in  which  the  lode  is  situated, 
within  a  specified  time  after  its  location. 


FORM  OF  RECORDING  LOCATION. 
STATE  OF     


COUNTY  OF ) 

Know  all  men  by  these  Presents,  That  I,  John  Doe, 

the  undersigned,  have  this  — th  day  of  A.D., 

1 8 — ,  located  and  claimed,  and  by  these  presents  do 
locate  and  claim,  by  right  of  discovery  and  location, 
in  compliance  with  the  Mining  Acts  of  Congress, 
approved  May  igth,  A.D.  1872,  and  all  subsequent 
Acts,  and  with  local  custom,  laws,  and  regulations, 

feet  linear  and  horizontal  measurement,  on  the 

-lode,  along  the  vein  thereof,  with  all  its  dips, 

angles,  and  variations,  together  with feet,  run- 
ning   from  center  of  discovery  shaft.  Said  dis- 
covery shaft  being  situated  upon  said  lode,  and  within 

the  lines  of  said  claim Mining  District,  County 

of ,  and  State  of ,  and  further  described 

as  follows: 

Beginning1  at  the  location  stake  and  running  in  a 
line  southwesterly  300  feet,  thence  northwesterly  to  a 
post  150  feet. 

Beginning  at  this  post  and  running  a  line  north- 
easterly 1500  feet,  to  a  point  marked  by  post  and  pile 
of  stones;  hence  southeasterly  600  feet  to  a  post  placed 
in  the  ground  and  marked  II;  hence  southwesterly 

1  Explanatory  only.     See  Fig.  66. 


342  UNITED  STATES  MINE  LAWS 

1500  feet  to  a  point  marked  by  post  and  stone  pile;  anc1 
thence  600  feet  northwesterly  to  the  point  of  beginning. 

Said  lode  was  located  on  the  — th  day  of  , 

A.D.  18— . 

JOHN  DOE. 
Attest: 

— th  day  of ,  A.D.  18 — . 

In  order  to  hold  possessory  rights  to  a  claim  of  1500 
feet  of  vein  or  lode  located  as  aforesaid,  the  Act  requires 
that  until  a  patent  shall  have  been  issued  therefor 
not  less  than  $100  worth  of  labor  shall  have  been  ex- 
pended annually,  on  the  basis  adopted  by  the  local 
mining  regulations;  in  default  of  which  labor  or  improve- 
ments the  claim  will  be  subject  to  relocation  by  any 
other  party  having  the  necessary  qualifications,  unless 
the  original  locator,  his  heirs,  assigns,  or  legal  repre- 
sentatives have  resumed  work  thereon  after  such  failure 
and  before  such  relocation. 

The  importance  of  attending  to  these  details  in  the 
matter  of  location,  labor,  and  expenditure  will  be  the 
more  readily  perceived  when  it  is  understood  that 
failure  to  do  so  may  invalidate  the  claim.  After  the 
patent  has  been  granted,  no  more  assessment  work  is 
required. 

Five  dollars  per  day  is  usually  allowed  for  each  day 
of  every  eight  hours'  work  performed  upon  a  claim  for 
the  purpose  of  holding  title  or  performing  the  neces- 
sary amount  of  work  for  the  patent,  and  no  other 
expenses  shall  be  considered  as  expended  for  the  pur- 
pose of  holding  or  protecting  title. 


PLACER  CLAIMS  343 

PLACER  CLAIMS. 

The  U.  S.  law  prior  to  May  10,  1872,  allowed  each 
person  160  acres  or  a  quarter  section  of  a  square  mile 
of  placer  ground,  if  located.  From  the  above  date 
all  placer  claims  shall  conform  as  nearly  as  practicable 
with  the  United  States  system  of  public  surveys,  and 
no  such  location  shall  include  more  than  20  acres  for 
each  individual  claimant.  The  provisions  of  the  law 
are  construed  by  the  Commissioner  of  the  General  Land 
Office  to  mean  that  after  the  gth  of  July,  1870,  no  loca- 
tion of  placer  claim  can  exceed  160  acres,  whatever 
may  be  the  number  of  locators  associated  together,  or 
whatever  the  local  regulation  of  the  district  may  allow; 
and  that  from  and  after  May  10,  1872,  no  location 
made  by  an  individual  can  exceed  20  acres,  and  no 
location  made  by  an  association  of  individuals  can  exceed 
1 60  acres;  which  location  cannot  be  made  by  a  less 
number  than  eight  bona-fide  locators.  But  whether  as 
much  as  20  acres  can  be  located  by  an  individual,  or 
1 60  acres  by  an  association,  depends  entirely  upon  the 
mining  regulations  in  force  in  the  respective  districts 
at  the  date  of  location;  it  being  held  that  such  mining 
regulations  are  in  no  way  enlarged  by  the  statutes,  but 
remain  intact  in  full  force  with  regard  to  the  size  of  lo- 
cations, in  so  far  as  they  do  not  permit  locations  in  excess 
of  the  limits  fixed  by  Congress.  A  local  regulation  is  valid 
which  provides  that  a  placer  claim,  for  instance,  shall 
not  exceed  100  feet  square.  Congress  requires  no 
annual  expenditures  on  placer  claims,  leaving  them 
subject  to  the  local  laws,  rules,  regulations,  and  customs 
of  the  mining  district. 


344  UNITED  STATES  MINE  LAWS 

The  California  Law  regarding  Placers.  —  Section  4, 
Act  of  1897,  reads: 

"The  discoverer  of  placers  or  other  forms  of  deposit, 
subject  to  location  and  appropriation  under  mining  laws 
applicable  to  placers,  shall  locate  his  claim  in  the  follow- 
ing manner: 

"First.  He  must  immediately  post,  in  a  conspicuous 
place  at  the  point  of  discovery  thereon,  a  notice  or  certi- 
ficate of  location  thereof,  containing: 

11  a.   The  name  of  the  claim. 

"b.   The  name  of  the  locator  or  locators. 

"c.  The  date  of  discovery  and  posting  of  the  notice 
hereinbefore  provided  for,  which  shall  be  considered  as 
the  date  of  location. 

"d.  A  description  of  the  claim  by  reference  to  legal 
subdivisions  or  sections,  if  the  location  is  made  in  con- 
formity with  the  public  surveys;  otherwise,  a  description 
with  reference  to  some  natural  object  or  permanent 
monument  as  will  identify  the  claim;  and  where  such 
claim  is  located  by  legal  subdivisions  of  the  public  surveys 
such  location  shall,  notwithstanding  that  fact,  be  marked 
by  the  locator  upon  the  ground,  the  same  as  other  loca- 
tions. 

"Second.  Within  thirty  days  from  the  date  of  such 
discovery  he  must  record  such  notice  or  certificate  of 
location  in  the  office  of  the  county  recorder  of  the  county 
in  which  such  discovery  is  made,  and  so  distinctly  mark 
his  location  on  the  ground  that  its  boundaries  can  be 
readily  traced. 

"Third.  Within  sixty  days  from  the  date  of  the  dis- 
covery the  discoverer  shall  perform  labor  upon  such 


CALIFORNIA  PLACER  CLAIMS  345 

location  or  claim  in  developing  same  to  an  amount  which 
shall  be  equivalent  in  the  aggregate  to  at  least  ten  dollars 
($10)  worth  of  such  labor  for  each  twenty  acres,  or  frac- 
tional part  thereof,  contained  in  such  location  or  claim. 

"Fourth.  A  failure  to  perform  such  labor  within  said 
time  shall  cause  all  rights  under  such  location  to  be  for- 
feited, and  the  discovery  thereby  shall  at  once  be  open 
to  location  by  qualified  locators  other  than  the  preceding 
locators,  but  shall  not  in  any  event  be  open  to  location 
by  such  preceding  locators,  and  any  labor  performed  by 
them  thereon  shall  not  inure  to  the  benefit  of  any  subse- 
quent locator  thereof. 

"  Fifth.  Such  locator  shall,  upon  the  performance  of 
such  labor,  file  with  the  recorder  of  the  county  an  affi- 
davit showing  such  performance,  and  generally  the  nature 
and  kind  of  work  so  done." 

Section  5  of  the  same  Act  reads:  "The  affidavit  pro- 
vided for  in  the  last  section,  and  the  aforesaid  placer 
notice  or  certificate  of  location  when  filed  for  location, 
shall  be  deemed  and  considered  as  prima  facie  evidence 
of  the  facts  therein  recited.  A  copy  of  such  certificate, 
notice,  or  affidavit,  certified  by  the  county  recorder,  shall 
be  admitted  in  evidence  in  all  actions  or  proceedings 
with  the  same  effect  as  the  original." 

In  locating  a  claim,  if  the  above  directions  are  closely 
followed,  no  matter  what  the  locality,  the  prospector  will 
generally  have  complied  with  the  law.  However,  it  is 
better  to  have  the  local  laws  well  understood  whenever 
possible. 

The  United  States  statutes  provide  "water  rights." 

i.   That  as  a  condition  of  sale,  in  the  absence  of  legis- 


346  UNITED  STATES  MINE  LAWS 

lation  by  Congress,  the  legislature  of  a  State  or  Territory 
may  provide  rules  for  working  mines,  involving  ease- 
ments, drainage,  and  other  necessary  conditions;  these 
to  be  expressed  in  the  patent. 

2.  All  prior  rights,  arising  from  possession,  in  the  use 
of  water,  and  recognized  by  local  laws,  etc.,  or  judicial 
decisions,  shall  be  regarded  as  vested,  and  shall  be  pro- 
tected.    This  right  of  way  is  also  granted  and  confirmed. 
Damages  are  to  accrue  if  a  land  settler's  rights  are  inter- 
fered with. 

3.  All  land  patents  shall  be  subject  to  vested  and 
accrued  water  rights,  including  ditches  and  reservoirs. 
Officers  of  the  U.  S.  Land  Office  are  required  to  file  with 
the  General  Land  Office  the  local  laws  on  such  matters. 
Water  privileges  are,  since  the  Act  of  May  10,   1872, 
located  in  the  same  manner  as  mines,  subject  to  local 
regulations,  i.e.,  by  definitely  locating  the  five  acres  by 
monuments,  and  recording  with  the  district  or  county 
recorder.     If  the  local  rules  and  decisions  of  courts  make 
the  privilege  forfeitable  for  non-use,  another  party  may 
come  in  and  claim  the  water  right.     The  Federal  courts 
have  decided  that  the  right  of  way  to  construct  flumes  or 
ditches  over  public  lands  is  unquestionable.     It  has  also 
been  decided  that  the  miner's  right  to  water,   within 
"reasonable  limits,"  is  not  to  be  questioned.     "It  must 
be  exercised,  however,  with  due  regard  to  the  general 
condition  and  needs  of  the  community,  and  cannot  vest 
as  an  individual  monopoly." 


MILL  SITES  347 

MILL  SITES. 

Land,  non-mineral  in  character,  and  not  contiguous 
to  the  vein  or  lode,  used  by  the  locator  and  proprietor 
for  mining  or  milling  purposes,  can  be  included  in  any 
application  for  patent,  to  an  extent  not  to  exceed  five  acres, 
and  subject  to  examination  and  payment  as  fixed  for  the 
superficies  of  the  lode.  The  owner  of  a  quartz  mill  or 
reduction  mill,  not  a  mine  owner  in  connection  therewith, 
may  also  receive  a  mill  site  patent.  Such  sites  are  located 
under  the  mining  act,  and  in  compliance  with  local  law 
and  customs  as  recognized.  Such  possessory  rights  give 
title  also  to  all  growing  timber  thereon.  There  must  in 
every  case  be  given  satisfactory  proof  of  the  non-mineral 
character  of  the  site,  and  the  improvements  thereon 
must  be  equal  to  $500.  A  mill  passes  to  a  railroad  if 
located  on  railroad  land  grant,  and  presumably  to  some- 
one else  if  located  on  another's  ground.  The  location 
of  a  mill  site  is  of  considerable  importance,  and  should 
be  examined  thoroughly.  It  must  be  surveyed  by  a 
Deputy  Mineral  Land  surveyor,  and  recorded  the  same 
as  a  lode  or  placer  claim. 


CHAPTER  XIV. 

THE  MINING  REGULATIONS   FOR  THE  CANADIAN 
YUKON. 

WE  give  below,  substantially  in  full,  the  new  regula- 
tions governing  placer  mining  and  dredging  in  the  pro- 
visional district  of  the  Yukon,  as  approved  by  Order  in 
Council  dated  Ottawa,  January  18,  1898.  These  regu- 
lations constitute  the  mining  law  under  which  all  opera- 
tions must  be  conducted  in  that  portion  of  the  Yukon 
region  which  is  in  Canadian  territory;  and  the  Dominion 
Government  is  making  provisions  for  their  strict  enforce- 
ment. The  regulations  are  as  follows : 

INTERPRETATION. 

"Free  Miner"  shall  mean  a  male  or  female  over  the 
age  of  1 8,  but  not  under  that  age,  or  joint-stock  com- 
pany, named  in,  and  lawfully  possessed  of,  a  valid  exist- 
ing free  miner's  certificate,  and  no  other. 

"Legal  Post"  shall  mean  a  stake  standing  not  less 
than  4  feet  above  the  ground  and  flatted  on  two  sides  for 
at  least  i  foot  from  the  top.  Both  sides  so  flatted  shall 
measure  at  least  4  inches  across  the  face.  It  shall  also 
mean  any  stump  or  tree  cut  off  and  flatted  or  faced  to  the 
above  height  and  size. 

"Close  Season"  shall  mean  the  period  of  the  year 
during  which  placer  mining  is  generally  suspended. 

348 


FREE-MINER'S   CERTIFICATE  349 

The  period  to  be  fixed  by  the  mining  recorder  in  whose 
district  the  claim  is  situated. 

1 1 Mineral"  shall  include  all  minerals  whatsoever 
other  than  coal. 

" Joint-stock  Company"  shall  mean  any  company 
incorporated  for  mining  purposes  under  a  Canadian 
charter  or  licensed  by  the  Government  of  Canada. 

" Mining  Recorder"  shall  mean  the  official  appointed 
by  the  gold  commissioner  to  record  applications  and 
grant  entries  for  claims  in  the  mining  divisions  into  which 
the  commissioner  may  divide  the  Yukon  District. 

FREE  MINERS  AND  THEIR  PRIVILEGES. 

1.  Every   person    over   but   not   under    18    years    of 
age,  and  every  joint-stock  company,   shall  be  entitled 
to  all  the  rights  and  privileges  of  a  free  miner,  under 
these  regulations  and  under  the  regulations  governing 
quartz  mining,   and  shall  be  considered  a  free  miner 
upon    taking    out    a    free-miner's    certificate.     A    free 
miner's  certificate  issued  to  a  joint-stock  company  shall 
be  issued  in  its  corporate  name.     A  free-miner's  certi- 
ficate shall  not  be  transferable. 

2.  A  free-miner's  certificate  may  be  granted  for  one 
year  to  run  from  the  date  thereof  or  from  the  expira- 
tion  of  the  applicant's   then   existing  certificate,   upon 
the  payment  therefor  of  the   sum  of  $10,   unless   the 
certificate  is  to  be  issued  in  favor  of  a  joint-stock  com- 
pany, in  which  case  the  fee  shall  be  $50  for  a  company 
having  a  nominal  capital  of  $100,000  or  less,  and  for  a 
company  having  a  nominal  capital  exceeding  $100,000, 


350  MINING   REGULATIONS  FOR  YUKON 

the  fee  shall  be  $100.     Only  one  person  or  joint-stock 
company  shall  be  named  in  a  certificate. 

3.  Gives  form  of  miner's  certificate,  and  adds:  This 
certificate   shall   also   grant   to   the   holder   thereof  the 
privileges  of  fishing  and  shooting,  subject  to  the  provi- 
sions of  any  act  which  has  been  passed,  or  which  may 
hereafter  be   passed,  for   the   protection   of  game   and 
fish;   also   the   privilege   of   cutting   timber   for   actual 
necessities,  for  building  houses,  boats,  and  for  general 
mining  operations;  such  timber,  however,  to  be  for  the 
exclusive  use  of  the  miner  himself,  but  such  permission 
shall  not  extend  to  timber  which  may  have  been  here- 
tofore or  which  may  hereafter  be  granted  to  other  per- 
sons or  corporations. 

4.  Free-miner's    certificates    may    be    obtained    by 
applicants  in  person  at  the  Department  of  the  Interior^ 
Ottawa,  or  from  the  agents   of    Dominion    Lands  at 
Winnipeg,  Manitoba;  Calgary,  Edmonton,  Prince  Albert, 
in  the  Northwest  Territories;  Kamloops  and  New  West- 
minster, in  the  Province  of  British  Columbia;  at  Dawson 
City  in  the  Yukon   District;  also  from  agents  of  the 
government  at  Vancouver  and  Victoria,  British  Colum- 
bia, and  at  other  places  which  may  from  time  to  time 
be  named  by  the  Minister  of  the  Interior. 

5.  If  any  person  or  joint-stock  company  shall  apply 
for  a  free-miner's  certificate  at  the  agent's  office  dur- 
ing his  absence,  and  shall  leave  the  fee  required  by 
these  regulations,   with  the  officer  or  other  person  in 
charge  of  said  office,  he  or  it  shall  be  entitled  to  have 
such  certificate  from  the  date  of  such  application;  and 
any  free  miner  shall  at  any  time  be  entitled  to  obtain 


SUBSTITUTED   CERTIFICATE  351 

a  free-miner's  certificate  commencing  to  run  from  the 
expiration  of  his  then  existing  free-miner's  certificate, 
provided  that  when  he  applies  for  such  certificate  he 
shall  produce  to  the  agent,  or  in  case  of  his  absence 
shall  leave  with  the  officer  or  other  person  in  charge 
of  the  agent's  office,  such  existing  certificate. 

6.  If    any    free-miner's    certificate    be    accidentally 
destroyed  or  lost,  the  owner  thereof  may,   on  payment 
of  a  fee  of  $2,  have  a  true  copy  of  it,  signed  by  the  agent, 
or  other  person  by  whom  or  out  of  whose  office  the 
original  was  issued.     Every  such  copy  shall  be  marked 
"Substituted    Certificate";    and    unless    some    material 
irregularity  be  shown  in  respect  thereof,  every  original 
or  substituted  free-miner's  certificate  shall  be  evidence 
of  all  matters  therein  contained. 

7.  No  person  or  joint-stock  company  will  be  recog- 
nized as  having  any  right  or  interest  in  or  to  any  placer 
claim,    quartz    claim,    mining    lease,    bed-rock    flume 
grant,  or  any  minerals  in  any  ground  comprised  therein, 
or  in  or  to  any  water  right,  mining  ditch,  drain,  tunnel, 
or  flume,  unless  he  or  it  and  every  person  in  his  or  its 
employment  shall   have  a  free-miner's  certificate  unex- 
pired.     And  on  the  expiration  of  a  free-miner's  certi- 
ficate the  owner  thereof   shall  absolutely  forfeit  all  his 
rights  and  interest  in  or  to  any  placer  claim,  mining 
lease,  bed-rock   flume  grant,  and  any  minerals  in  any 
ground  comprised  therein,  and  in  or  to  any  and  every 
water  right,  mining  ditch,  drain,  tunnel,  or  flume,  which 
may  be  held  or  claimed  by  such  owner  of  such  expired 
free-miner's  certificate,  unless  such  owner  shall,  on  or 
before  the  day  following  the  expiration  of  such  certifi- 


352  MINING  REGULATIONS  FOR  YUKON 

cate,  obtain  a  new  free-miner's  certificate.  Provided, 
nevertheless,  that  should  any  co-owner  fail  to  keep  up 
his  free-miner's  certificate  such  failure  shall  not  cause  a 
forfeiture  or  act  as  an  abandonment  of  the  claim,  but 
the  interest  of  the  co-owner  who  shall  fail  to  keep  up 
his  free-miner's  certificate  shall,  ipso  facto,  be  and  become 
vested  in  his  co-owners,  pro  rata  according  to  their 
former  interests;  provided,  nevertheless,  that  a  share- 
holder in  a  joint-stock  company  need  not  be  a  free 
miner,  and,  though  not  a  free  miner,  shall  be  entitled  to 
buy,  sell,  hold  or  dispose  of  any  shares  therein. 

8.  Every   free   miner  shall,   during  the   continuance 
of  his  certificate,  but  not  longer,  have  the  right  to  enter, 
locate,  prospect,  and  mine  for  gold  and  other  minerals 
upon  any  lands  in  the  Yukon  District,  whether  vested 
in  the   Crown  or  otherwise,   except  upon  government 
reservations  for  town  sites,  land  which  is  occupied  by 
any  building,  and  any  land  falling  within  the  curtilage 
of  any  dwelling-house,  and  any  land  lawfully  occupied 
for  placer-mining  purposes,  and  also  Indian  reservations. 

9.  Previous   to   any   entry   being   made   upon   lands 
lawfully  occupied,  such  free  miner  shall  give  adequate 
security,    to   the   satisfaction   of   the   mining   recorder, 
for  any  loss  or  damage  which  may  be  caused  by  such 
entry;  and  after  such  entry  he  shall  make  full  com- 
pensation to  the  occupant  or  owner  of  such  lands  for 
any  loss  or  damage  which  may  be  caused  by  reason  of 
such  entry;  such  compensation,  in  case  of  dispute,  to 
be  determined  by  a  court  having  jurisdiction  in  min- 
ing disputes,  with  or  without  a  jury. 


SIZE  OF  CLAIMS 


353 


NATURE  AND  SIZE  OF  CLAIMS. 

10.  A  creek  or  gulch  claim  shall  be  250  feet  long 
measured  in  the  general  direction  of  the  creek  or  gulch. 
The  boundaries  of  the  claim  which  run  in  the  general 
direction  of  the  creek  or  gulch  shall  be  lines  along  bed 
or  rim  rock  3  feet  higher  than  the  rim  or  edge  of  the 
creek,  or  the  lowest  general  level  of  the  gulch  within 
the  claim,  so  drawn  or  marked  as  to  be  at  every  point 


i 


Post 


"i          r 
i!     i     it 

03'  O  [03 


No.  i. — PLAN  AND  SECTIONS  OF  CREEK  AND  GULCH  CLAIMS. 

3  feet  above  the  rim  or  edge  of  the  creek  or  the  lowest 
general  level  of  the  gulch,  opposite  to  it  at  right  angles 
to  the  general  direction  of  the  claim  for  its  length,  but 
such  boundaries  shall  not  in  any  case  exceed  1000  feet 


354          MINING  REGULATIONS  FOR  YUKON 

on  each  side  of  the  center  of  the  stream  or  gulch.     (See 
Diagram  No.  i.) 

ii.  If  the  boundaries  be  less  than  100  feet  apart 
horizontally,  they  shall  be  lines  traced  along  bed  or 
rim  rock  100  feet  apart  horizontally,  following  as  nearly 
as  practicable  the  direction  of  the  valley  for  the  length 
of  the  valley  for  the  length  of  the  claim.  (See  Dia- 
gram No.  2.) 


100  feet 


No.  2. — SIDE  BOUNDARIES  LESS  THAN  100  FT.  APART. 

12.  A  river  claim  shall  be  situated  only  on  one  side 
of  the  river  and  shall  not  exceed  250  feet  in  length, 
measured  in  the  general  direction  of  the  river.  The 
other  boundary  of  the  claim  which  runs  in  the  general 
direction  of  the  river  shall  be  lines  along  bed  or  rim 
rock  3  feet  higher  than  the  rim  or  edge  of  the  river 
within  the  claim  so  drawn  or  marked  as  to  be  at  every 
point  3  feet  above  the  rim  or  edge  of  the  river  opposite 
to  it  at  right  angles  to  the  general  direction  of  the  claim 
for  its  length,  but  such  boundaries  shall  not  in  any 
case  be  less  than  250  feet  or  exceed  a  distance  of  1000 
feet  from  low- water  mark  of  the  river.  (See  Diagram 
No.  3.) 


CREEK  CLAIMS 


355 


13.  A  "hill  claim"  shall  not  exceed  250  feet  in  length, 
drawn  parallel  to  the  main  direction  of  the  stream  or 
ravine  on  which  it  fronts.  Parallel  lines  drawn  from 


No.  3.— SECTION  OF  RIVER  CLAIM. 

each  end  of  the  base  at  right  angles  thereto,  and  running 
to  the  summit  of  the  hill  (provided  the  distance  does 
not  exceed  1000  feet),  shall  constitute  the  end  boundaries 
of  the  claim. 

14.  All  other  placer  claims  shall  be  250  feet  square. 

15.  Every  placer  claim  shall  be  as  nearly  as  possible 
rectangular  in  form,   and  marked  by  two  legal   posts 
firmly  fixed   in  the  ground  in  the  manner   shown   in 
Diagram  No.  4.     The  line  between  the  two  posts  shall 


Post 


Post 


2 
$L 


Post 


Post 


No.  4. — STAKING  CREEK  AND  RIVER  CLAIMS. 

be  well  cut  out  so  that  one  post  may,  if  the  nature  of 
the  surface  will  permit,  be  seen  from  the  other.  The 
flatted  side  of  each  post  shall  face  the  claim,  and  on 


356          MINING  REGULATIONS  FOR  YUKON 

each  post  shall  be  written  on  the  side  facing  the  claim, 
a  legible  note  stating  the  name  or  number  of  the  claim, 
or  both  if  possible,  its  length  in  feet,  the  date  when 
staked,  and  the  full  Christian  and  surname  of  the 
locator. 

1 6.  Every  alternate  10  claims  shall  be  reserved  for 
the  Government  of  Canada.     That  is  to  say,  when  a 
claim  is  located  the  discoverer's  claim  and  9  additional 
claims   adjoining   each   other   and   numbered   consecu- 
tively will   be  open  for  registration.     Then   the   next 
10  claims  of  250  feet  each  will  be  reserved  for  the  Gov- 
ernment,  and  so  on.     The  alternate  group  of  claims 
reserved  for  the  Crown  shall  be  disposed  of  in  such 
manner  as   may  be  decided   by  the   Minister  of  the 
Interior. 

17.  The   penalty  for  trespassing  upon  a  claim  re- 
served for  the  Crown  shall  be  immediate  cancellation 
by  the  mining  recorder  for  any  entry  or  entries  which 
the  person  trespassing  may  have  obtained,  whether  by 
original   entry  or  purchase,   for  a   mining  claim,   and 
the  refusal  by  the  mining  recorder  of  the  acceptance 
of  any  application  which  the  person  trespassing  may 
at  any  time  make  for  a  claim.     In  addition  to  such 
penalty,  the  mounted  police,  upon  a  requisition  from 
the  mining  recorder  to  that  effect,  shall  take  the  neces- 
sary steps  to  eject  the  trespasser. 

1 8.  In    defining    the  size  of    claims,   they  shall   be 
measured    horizontally    irrespective    of   inequalities    on 
the  surface  of  the  ground. 

19.  If  any  free  miner  or  party  of  free  miners  dis- 
cover a  new  mine,  and  such  discovery  shall  be  estab- 


FREE-MINERS'   RECORDER  357 

lished  to  the  satisfaction  of  the  mining  recorder,  creek, 
river,  or  hill,  claims  of  the  following  size  shall  be  al- 
lowed, namely:  To  one  discoverer,  one  claim,  500  feet 
in  length.  To.  a  party  of  two  discoverers,  two  claims, 
amounting  together  to  1000  feet  in  length.  To  each 
member  of  a  party  beyond  two  in  number,  a  claim  of 
the  ordinary  size  only. 

20.  A  new  stratum   of    auriferous  earth  or  gravel 
situated  in  a  locality  where  the  claims  have  been  aban- 
doned  shall   for  this  purpose  be  deemed  a  new  mine, 
although   the  same  locality  shall   have  been  previously 
worked  at  a  different  level. 

21.  The  forms  of  application  for  a  grant  for  placer 
mining,  and  the  grant  of  the  same,  shall  be  those  con- 
tained in  forms  H  and  I  in  the  schedule  hereto. 

22.  A  claim  shall  be  recorded  with  the  mining  recorder 
in  whose  district  it  is  situated,  within  10  days  after  the 
location  thereof,  if  it  is  located  within  10  miles  of  the 
mining  recorder's  office.     One  extra  day  shall  be  allowed 
for  every  additional  10  miles  or  fraction  thereof. 

23.  In  the  event  of  the  claim  being  more  than  100 
miles  from  a  recorder's  office,  and  situated  where  other 
claims  are  being  located,  the  free  miners,  not  less  than 
five  in  number,  are  authorized  to  meet  and  appoint  one 
of  their  number  a  "  Free-miners'  Recorder,"  who  shall 
act  in  that  capacity  until  a  mining  recorder  is  appointed 
by  the  gold  commissioner. 

24.  The  free-miners'  recorder  shall,  at  the  earliest 
possible  date  after  his  appointment,  notify  the  nearest 
Government   mining   recorder   thereof,    and   upon   the 
arrival  of    the  Government   mining   recorder  he  shall 


358          MINING  REGULATIONS  FOR  YUKON 

deliver  to  him  his  records  and  the  fees  received  for 
recording  the  claims.  The  Government  mining  re- 
corder shall  then  grant  to  each  free  miner  whose  name 
appears  in  the  records  an  entry  for  his  claim  on  form 
I  of  these  regulations,  provided  an  application  has 
been  made  by  him  in  accordance  with  form  H  thereof. 
The  entry  to  date  from  the  time  the  free-miners'  re- 
corder recorded  the  application. 

25.  If   the   free-miners'    recorder   fails    within   three 
months    to    notify    the    nearest     Government    mining 
recorder  of  his  appointment,  the  claims  which  he  may 
have  recorded  will  be  cancelled. 

26.  During  the  absence  of  the  mining  recorder  from 
his  office,  the  entry  for  a  claim  may  be  granted  by  any 
person  whom  he  may  appoint  to  perform  his  duties  in 
his  absence. 

27.  Entry  shall  not  be  granted  for  a  claim  which  has 
not  been  staked  by  the  applicant  in  person  in  the  manner 
specified   in   these   regulations.     An   affidavit   that   the 
claim  was  staked  out  by  the  applicant  shall  be  embodied 
in  form  H  in  the  schedule  hereto. 

28.  An  entry  fee  of  $15  shall  be  charged  the  first 
year,  and  an  annual  fee  of  $15  for  each  of  the  following 
years.     This  provision  shall  apply  to  claims  for  which 
entries  have  already  been  granted. 

29.  A  statement  of  the  entries  granted  and  fees  col- 
lected shall  be  rendered  by  the  mining  recorder  to  the 
gold  commissioner  at  least  every  three  months,  which 
shall  be  accompanied  by  the  amount  collected. 

30.  A  royalty  of  10  per  cent  on  the  gold  mined  shall 
be  levied  and  collected  on  the  gross  output  of  each 


ROYALTY  359 

claim.  The  royalty  may  be  paid  at  banking  offices  to 
be  established  under  the  auspices  of  the  Government 
of  Canada,  or  to  the  gold  commissioner,  or  to  any  mining 
recorder  authorized  by  him.  The  sum  of  $2500  shall 
be  deducted  from  the  gross  annual  output  of  a  claim 
when  estimating  the  amount  upon  which  royalty  is  to 
be  calculated,  but  this  exemption  shall  not  be  allowed 
unless  the  royalty  is  paid  at  a  banking  office  or  to  the 
gold  commissioner  or  mining  recorder.  When  the 
royalty  is  paid  monthly  or  at  longer  periods,  the  deduc- 
tion shall  be  made  ratable  on  the  basis  of  $2500  per 
annum  for  the  claim.  If  not  paid  to  the  bank,  gold 
commissioner,  or  mining  recorder,  it  shall  be  collected 
by  the  custom  officials  or  police  officers  when  the  miner 
passes  the  posts  established  at  the  boundary  of  a  district. 
Such  royalty  to  form  part  of  the  consolidated  revenue, 
and  to  be  accounted  for  by  the  officers  who  collect  the 
same  in  due  course.  The  time  and  manner  in  which 
such  royalty  shall  be  collected  shall  be  provided  for 
by  regulations  to  be  made  by  the  gold  commissioner. 

31.  Default  in  payment  of  such  royalty,  if  continued 
for  10  days  after  notice  has  been  posted  on  the  claim 
in  respect  of  which  it  is  demanded,  or  in  the  vicinity 
of  such  claim,  by  the  gold  commissioner  or  his  agent, 
shall  be  followed  by  cancellation  of  the  claim.  Any 
attempt  to  defraud  the  Crown  by  withholding  any  part 
of  the  revenue  thus  provided  for,  by  making  false  state- 
ments of  the  amount  taken  out,  shall  be  punished  by 
cancellation  of  the  claim  in  respect  of  which  fraud  or 
false  statements  have  been  committed  or  made.  In 
respect  to  the  facts  as  to  such  fraud  or  false  statements 


360  MINING  REGULATIONS  FOR  YUKON 

or  non-payment   of  royalty,   the   decision   of  the   gold 
commissioner  shall  be  final. 

32.  After  the  recording  of  a  claim  the  removal  of 
any  post  by  the  holder  thereof  or  by  any  person  act- 
ing in  his  behalf,  for  the  purpose  of  changing  the  boun- 
daries of  his  claim,  shall  act  as  a  forfeiture  of  the  claim. 

33.  The  entry  of  every  holder  of  a  grant  -for  placer 
mining  must  be  renewed  and  his  receipt  relinquished 
and  replaced  every  year,  the  entry  fee  being  paid  each 
time. 

34.  The  holder  of  a  creek,  gulch,  or  river  claim  may, 
within  60  days  after  staking  out  the  claim,  obtain  an 
entry  for  a  hill  claim  adjoining  it,   by  paying  to  the 
mining  recorder  the   sum    of    $100.     This   permission 
shall  also  be  given  to  the  holder  of  a  creek,  gulch,  or 
river    claim    obtained    under    former   regulations,    pro- 
vided that  the  hill  claim  is  available  at  the  time  an 
application  is  made  therefor. 

35.  No   miner  shall   receive   a   grant   of  more   than 
one  mining  claim  in  a  mining  district,  the  boundaries 
of  which  shall  be  defined  by  the  mining  recorder,  but 
the  same  miner  may  also  hold  a  hill  claim,  acquired 
by  him  under  these  regulations  in  connection  with  a 
creek,  gulch,  or  river  claim,  and  any  number  of  claims 
by  purchase;  and  any  number  of  miners  may  unite  to 
work   their   claims   in   common,    upon   such   terms   as 
they  may  arrange,   provided   such  agreement  is  regis- 
tered with  the  mining  recorder  and  a  fee  of  $5  paid 
for  each  registration. 

36.  Any  free  miner  or  miners  may  sell,   mortgage, 
or  dispose  of  his  or  their  claims,   provided  such  dis- 


ABANDONED   CLAIM  361 

posal  be  registered  with,  and  a  fee  of  $2  paid  to,  the 
mining  recorder,  who  shall  thereupon  give  the  assignee 
a  certificate  in  the  form  J  in  the  schedule  hereto. 

37.  Every  free  miner  shall  during  the  continuance 
of  his  grant  have  the  exclusive  right  of  entry  upon  his 
own  claim  for  the  mine- like  working  thereof,  and  the 
construction  of  a  residence  thereon,  and  shall  be  entitled 
exclusively  to  all  the  proceeds  realized  therefrom,  upon 
which,  however,  the  royalty  prescribed  by  these  regula- 
tions shall  be  payable;  provided  that  the  mining  recorder 
may  grant  to  the  holders  of  other  claims  such  right  of 
entry  thereon  as  may  be  absolutely  necessary  for  the 
working  of  their  claims,  upon  such  terms  as  may  to 
him  seem  reasonable.     He  may  also  grant  permits  to 
miners  to  cut  timber  thereon  for  their  own  use. 

38.  Every  free  miner  shall  be  entitled  to  the  use  of 
so    much   of   the   water   naturally   flowing   through   or 
past  his  claim,  and  not  already  lawfully  appropriated, 
as  shall,  in  the  opinion  of  the  mining  recorder,  be  neces- 
sary for  the  due  working  thereof,  and  shall  be  entitled 
to  drain  his  own  claim  free  of  charge. 

39.  A  claim  shall  be  deemed  to  be  abandoned  and 
open  to  occupation  and  entry  by  any  person  when  the 
same  shall  have  remained  unworked  on  working  days, 
excepting  during  the  close  season,  by  the  grantee  thereof 
or  by  some  person  on  his  behalf  for  the  space  of  72 
hours,    unless   sickness   or   other   reasonable   cause   be 
shown  to  the  satisfaction  of  the  mining  recorder,   or 
unless  the  grantee  is  absent  on  leave  given  by  the  mining 
recorder,    and    the    mining    recorder,    upon    obtaining 
evidence  satisfactory  to  himself  that  this  provision  is  not 


362  MINING  REGULATIONS  FOR  YUKON 

being  complied  with,  may  cancel  the  entry  given  for  a 
claim. 

40.  If  any  cases  arise  for  which  no  provision  is  made 
in  these  regulations,  the  provisions  of  the  regulations 
governing  the  disposal  of  mineral  lands  other  than 
coal  lands,  approved  by  His  Excellency  the  Governor  in 
Council  on  November  9,  1889,  or  such  other  regulations 
as  may  be  substituted  therefor,  shall  apply.  (Appended 
to  Section  40  are  the  forms  for  applications,  certificates, 
etc.,  referred  to  in  the  text.) 

REGULATIONS  GOVERNING  RIVER-BED  DREDGING 
FOR  GOLD. 

The  following  are  the  regulations  for  the  issues  of 
leases  to  persons  or  companies  who  have  obtained  a 
free-miner's  certificate  in  accordance  with  the  provi- 
sions of  the  regulations  governing  placer  mining  in  the 
Provisional  District  of  Yukon,  to  dredge  for  minerals 
other  than  coal  in  the  submerged  beds  or  bars  of  rivers 
in  the  Provisional  District  of  Yukon,  in  the  Northwest 
Territories : 

i.  The  lessee  shall  be  given  the  exclusive  right  to 
subaqueous  mining  and  dredging  for  all  minerals  with 
the  exception  of  coal  in  and  along  an  unbroken  extent 
of  five  miles  of  a  river  following  its  sinuosities,  to  be 
measured  down  the  middle  thereof,  and  to  be  described 
by  the  lessee  in  such  manner  as  to  be  easily  traced  on 
the  ground;  and  although  the  lessee  may  also  obtain  as 
many  as  five  other  leases,  each  for  an  unbroken  extent 
of  five  miles  of  a  river,  so  measured  and  described,  no 
more  than  six  such  leases  will  be  issued  in  favor  of  an 


TERM   OF  LEASE  363 

individual  or  company,  so  that  the  maximum  extent  of 
river  in  and  along  which  any  individual  or  company 
shall  be  given  the  exclusive  right  above  mentioned,  shall 
under  no  circumstances  exceed  30  miles.  The  lease 
shall  provide  for  the  survey  of  the  leasehold  under 
instructions  from  the  Surveyor  General,  and  for  the 
filing  of  the  returns  of  survey  in  the  Department  of  the 
Interior  within  one  year  from  the  date  of  the  lease. 

2.  The  lease  shall  be  for  a  term  of  20  years,  at  the 
end  of  which  time  all  rights  vested  in,  or  which  may 
be  claimed  by  the  lessee  under  his  lease,  are  to  cease 
and   determine.     The   lease   may   be   renewable,    how- 
ever, from  time  to  time  thereafter  in  the  discretion  of 
the  Minister  of  the  Interior. 

3.  The  lessee's  right  of  mining  and  dredging  shall 
be  confined  to  the  submerged  beds  or  bars  in  the  river 
below  low-water  mark,  that  boundary  to  be  fixed  by 
its  position  on  the  first  day  of  August  in  the  year  of  the 
date  of  the  lease. 

4.  The  lease  shall   be  subject  to  the  rights  of  all 
persons  who  have  received  or  who  may  receive  entries 
for  claims  under  the  Placer- mining  Regulations. 

5.  The   lessee   shall    have   at   least   one   dredge   in 
operation  upon  the  five  miles  of  river  leased  to  him, 
within  two  seasons  from  the  date  of  his  lease,  and  if, 
during  one  season  when  operations  can  be  carried  on, 
he  fails  to  efficiently  work  the  same  to  the  satisfaction 
of  the  Minister  of  the  Interior,  the  lease  shall  become 
null  and  void  unless  the  Minister  of  the  Interior  shall 
otherwise   decide.     Provided   that   when   any  company 
or  individual  has  obtained  more  than  one  lease,   one 


364          MINING  REGULATIONS  FOR  YUKON 

dredge  for  each  15  miles  or  portion  thereof  shall  be 
held  to  be  compliance  with  this  regulation. 

6.  The  lessee  shall  pay  a  rental  of  $100  per  annum 
for  each  mile  of  river  so  leased  to  him.     The  lessee 
shall  also  pay  to  the  Crown  a  royalty  of  10  per  cent 
on  the  output  in  excess  of  $15,000,  as  shown  by  sworn 
returns  to  be  furnished  monthly  by  the  lessee  to  the 
gold    commissioner    during    the    period    that    dredging 
operations  are  being  carried  on;  such  royalty,  if  any,  to 
be  paid  with  each  return. 

7.  The  lessee  who  is  the  holder  of  more  than  one 
lease  shall  be  entitled  to  the  exemption  as  to  royalty 
provided  for  by  the   next   preceding  regulation  to  the 
extent  of  $15,000  for  each  five  miles  of  river  for  which 
he  is  the  holder  of  a  lease;  but  the  lessee  under  one 
lease  shall  not  be  entitled  to  the  exemption  as  to  royalty 
provided  by  the  next  two  preceding  regulations,  where 
the  dredge  or  dredges  used  by  him  have  been  used  in 
dredging  by  another  lessee,  or  in  any  case  in  respect  of 
more  than  30  miles. 

8.  The  lessee  shall  be  permitted  to  cut  free  of  all 
dues,  on  any  land  belonging  to  the  Crown,  such  timber 
as  may  be  necessary  for  the  purposes  of  his  lease,  but 
such  permission  shall  not  extend  to  timber  which  may 
have  been   heretofore   or  may  hereafter  be  granted  to 
other  persons  or  corporations. 

9.  The  lessee  shall  not  interfere  in  any  way  with  the 
general  right  of  the  public  to  use  the  river  in  which  he 
may  be  permitted  to  dredge,  for  navigation  and  other 
purposes;  the  free  navigation  of  the  river  shall  not  be 
impeded  by  the  deposit  of  tailings  in  such  manner  as  to 


LEASE  RESTRICTIONS  365 

form  bars  or  banks  in  the  channel  thereof,  and  the 
current  or  stream  shall  not  be  obstructed  in  any  material 
degree  by  the  accumulation  of  such  deposits. 

10.  The  lease  shall  provide  that  any  person  who  has 
received  or  who  may  receive  entry  under  the  Placer-min- 
ing Regulations  shall  be  entitled  to  run  tailings  into  the 
river  at  any  point  thereon,  and  to  construct  all  works 
which  may  be  necessary  for  properly  operating  and  work- 
ing his  claim.     Provided  that  it  shall  not  be  lawful  for 
such  person  to  construct  a  wing  dam  within  1000  feet 
from  the  place  where  any  dredge  is  being  operated,  nor 
to  obstruct  or  interfere  in  any  way  with  the  operation  of 
any  dredge. 

11.  The  lease  shall  reserve  all  roads,  ways,  bridges, 
drains,  and  other  public  works,  and  all  improvement  now 
existing,  or  which  may  hereafter  be  made  in,  upon,  or 
under  any  part  of  the  river,  and  the  power  to  enter  and 
construct  the  same,  and  shall  provide  that  the  lessee 
shall  not  damage  nor  obstruct  any  public  ways,  drains, 
bridges,  works,  and  improvements  now  or  hereafter  to 
be  made  upon,  in,  over,  through,  or  under  the  river;  and 
that  he  will  substantially  bridge  or  cover  and  protect  all 
the  cuts,  flumes,  ditches,  and  sluices,  and  all  pits  and 
dangerous  places  at  all  points  where  they  may  be  crossed 
by  a  public  highway  or  frequented  path  or  trail,  to  the 
satisfaction  of  the  Minister  of  the  Interior. 

12.  That   the   lessee,    his   executors,    administrators, 
or  assigns,  shall  not  nor  will  assign,  transfer,  or  sublet  the 
demised  premises,  or  any  part  thereof,  without  the  con- 
sent in  writing  of  the  Minister  first  had  and  obtained. 


366          MINING  REGULATIONS  FOR  YUKON 

UNITED  STATES 
LAW  RELATIVE  TO  RIVER  DREDGING. 

Rivers  or  streams  in  a  defined  channel  belong  to  the 
State.  To  dredge  river  beds  requires  either  a  grant  or 
prescription  from  the  State,  in  the  absence  of  any  definite 
legislation  regulating  this  industry.  There  is  scarcely 
any  doubt  that  the  State  would  grant  permission  to  mine 
any  river  bed  within  her  borders  provided  navigation 
were  not  hindered  or  obstructed  or  riparian  rights  inter- 
fered with,  but  such  sanction  should  be  obtained  prior 
to  commencing  work.  In  the  case  of  a  non-navigable 
stream  flowing  within  the  borders  of  one's  land,  the  land 
under  the  water  belongs  to  the  landowner;  or  the  water, 
to  the  State.  In  such  a  case  the  right  to  dredge  is  un- 
questionable. Or  in  case  of  two  landowners  adjoining 
on  opposite  sides  either  one  may  dredge  his  half  and 
be  convicted  of  trespass  if  he  oversteps  the  boundary. 
The  owner  or  owners  must  not  overstep  the  mark  and 
injure  land  or  watercourse  below  their  property,  other- 
wise they  may  be  enjoined. 

The  dredging  company  may  purchase  a  piece  of  land 
and  work  their  dredge  along  the  river  bank.  They 
must  not,  however,  change  the  course  of  the  stream  or 
divert  it  from  the  riparian  owner  opposite,  although  they 
may  work  as  far  inland  on  their  own  property  as  they 
desire,  and  have  the  usufruct  of  the  stream.  The  chances 
are  that  dredgers  if  they  pollute  the  streams  or  make  them 
muddy  will  have  trouble  with  riparian  owners  in  the 
States  for  creating  a  nuisance.  The  washing  of  ore  and 
discoloring  the  water  of  the  New  River,  Virginia,  has 


WATER  RIGHTS  367 

caused  much  comment,  and  an  attempt  has  been  made 
in  Congress  to  suppress  it. 

The  Anthracite  Mine  Operators  are  compelled  to 
impound  the  material  resulting  from  coal  washing, 
where  once  they  permitted  it  to  run  into  the  streams 
and  rivers. 

If  the  stream  belongs  to  the  public  domain,  twenty 
acres  can  be  located,  or  a  dredger  may  work  up  and 
down  the  stream  (provided  it  does  not  work  on  a  located 
claim)  without  interference. 

Navigable  rivers  are  under  the  supervision  of  the 
United  States ;  other  streams  belong  to  the  States 
through  which  they  flow.  Mineral  lands  under  rivers 
belong  to  the  State,  and  can  be  obtained  from  the 
State  by  proper  legal  proceedings. 


CHAPTER  XV. 

GOLD  TABLE  AND  HYDRAULICS. 

THE  following  tables  have  been  computed  by  data 
obtained  from  careful  experiments  made  by  the  ablest 
engineers. 

They  will  therefore  assist  the  unskilled  as  well  as  the 
skilled  in  many  problems.  However,  to  thoroughly 
understand  the  subject,  one  should  purchase  a  text-book 
on  hydraulics. 

These  tables  are  reliable,  and  will  prove  correct  as  far 
as  they  go. 

The  whole  subject  has  been  touched  upon  in  the 
preceding  pages,  so  that  any  one  who  has  carefully  read 
them  should  understand  the  tables  at  a  glance,  and  be 
able  to  apply  them  in  practice. 

EXPLANATION  OF  TABLE. 

The  table  furnishes  an  exceedingly  simple  method  of 
determining  the  value  of  free  gold  in  a  ton  of  gold- 
bearing  quartz,  or  a  cubic  yard  of  auriferous  gravel. 

Take  a  sample  of  four  (4)  pounds  of  quartz,  pulverize 
it  to  the  usual  fineness  for  horning,  wash  it  carefully  by 
batea  or  other  means,  amalgamate  the  gold  by  the  appli- 
cation of  quicksilver,  volatilize  the  quicksilver  by  blow- 
pipe or  otherwise,  weigh  the  resulting  button,  and  the 

368 


GOLD  TABLE 


value  given  in  the  table  opposite  such  weight  will  be  the 
value  in  free  gold  per  ton  of  2000  pounds  of  quartz. 

Example.  —  Sample  of  four  pounds  produces  button 
weighing  one  grain,  the  fineness  of  the  gold  being  830; 
then  the  value  of  one  ton  of  such  quartz  will  be  $17.87. 

If  the  sample  of  4  pounds  should  produce  a  button 
weighing  say  two  and  four- tenths  (2^)  grains,  then  the 
value  of  such  quartz  would  be  (875  fine)  as  follows,  viz.: 

Opposite    2  grains,       875  fine,     value  $37.68 

Opposite  T%  grains,       875  fine,     value      7.53 

Total  value  per  ton  (2000  Ibs.)    .  .$45.21 

GOLD    TABLE 

FOR  DETERMINING  THE  VALUE  OF  FREE  GOLD  PER  TON  (2OOO  LBS.) 
OF  QUARTZ  OR  CUBIC  YARD  OF  GRAVEL, 

Prepared  by 
MELVILLE  AT  WOOD,  Esq.,  F.G.S.,  Consulting  Mining  Engineer. 


Weight 

Fineness, 

Fineness, 

Fineness, 

Fineness, 

Washed  Gold. 

780. 

830. 

875. 

920. 

4-lb  Sample. 
Grains. 

Value  per  Oz. 
$16.12. 

Value  per  Oz. 
$17.15. 

Value  per  Oz. 
$18.08. 

Value  per  Oz. 
19.01. 

5  grains 

$83.97 

$89.36 

$94.20 

$99.05 

4 

67.18 

71.49 

75  -36 

79.24 

3 

50-38 

53  -61 

56-52 

59-43 

2 

33-59 

35-74 

37.68 

39.62 

I 

16.79 

17.87 

18.84 

19.81 

•9 

15.11 

16.08 

16.95 

17.82 

.8 

13-43 

14.29 

15-07 

15.84 

•7 

n-75 

12.51 

13-19 

13.86 

.6 

10.07 

10-73 

11.30 

11.88 

•  5 

8.40 

8-93 

9.42 

9.90 

•4 

6.71 

7.14 

7-53 

7.92 

•3 

5-°3 

5-30 

5-65 

5-94 

.2 

3-36 

3-57 

3-76 

3-96 

.  I 

1.68 

1.78 

1.88 

1.98 

370  GOLD  TABLE  AND  HYDRAULICS 

GOLD  VALUE  OF  A  CUBIC  YARD  OF  GRAVEL. 

To  determine  the  gold  value  of  a  cubic  yard  of  aurif- 
erous gravel  the  foregoing  table  can  be  used. 

Take  a  sample  of  sixty  (60)  pounds  of  gravel,  pul- 
verize it,  and  carefully  wash  it  by  batea,  pan,  or  other- 
wise; amalgamate  the  gold,  volatilize  the  quicksilver, 
weigh  the  button,  and  in  column  in  foregoing  table,  oppo- 
site the  weight,  will  be  found  the  gold  value  of  a  cubic 
yard  of  the  gravel. 

Example.  —  Sample  of  sixty  pounds  produces  button 
weighing  one  grain,  the  fineness  of  the  gold  being  780; 
then  the  value  of  one  cubic  yard  of  such  gravel  would 
be  $1.67.  This  is  arrived  at  by  pointing  off  one  point, 
or  dividing  the  value  given  in  table  by  10. 

If  the  sample  of  sixty  pounds  yields  a  button  weighing 
i  grain  and  two-tenths  (itk  grains),  then  the  value  of 
the  gravel  per  cubic  yard  would  be  —  gold  being  920 
fine  —  as  follows : 

Opposite   i   grain,      920  fine,      value  $1.98 
Opposite  tiF  grain,      920  fine,      value      .40  + 

Total  value  cubic  yard     ....       $2.38  + 

This  table  is  prepared  upon  the  following  basis  of 
weights,  viz. :  A  sample  of  4  pounds  of  quartz  is  the  one- 
five-hundredth  part  in  weight  of  a  ton  of  2000  pounds, 
and  the  gold  values  given  are  reduced  to  this  proportion. 

Eighteen  cubic  feet  of  gravel  in  bank  will  weigh  one 
ton,  or  2000  pounds,  and  a  cubic  yard,  or  27  cubic  feet, 
will  weigh  3000  pounds,  or  i  J  tons;  and  60  pounds  being 
the  one-fiftieth  part  of  the  weight  of  a  cubic  yard,  then 


HYDRAULICS  371 

the  relative  proportion  of  the  weight  of  quartz  to  gravel 
is  as  50  to  500,  or  i  to  10. 

HYDRAULICS. 

i  gallon  of  water  =231  cubic  inches  and  weighs  8.3389  pounds, 
figured  at  8J  pounds. 

i  cubic  foot  of  water  =  1728  cubic  inches  and  weighs  62.3793  pounds, 
figured  at  62.5. 

contains  7.48052  gallons,  usually  figured 
at  7.5. 

A  column  of  water  2.31  feet  high  gives  i  Ib.  pressure  on  each  square 
inch  of  its  base. 

A  column  of  water  i  ft.  high  will  give  a  pressure  of  .434  Ib.  on  each 
square  inch  of  base.  Usually  reckoned  at 
5  Ibs.  per  ft.  in  height. 

Doubling  the  diameter  of  a  pipe  increases  its  area  four  times,  hence 
its  capacity. 

Doubling  the  diameter  of  a  pipe  increases  its  frictional  rubbing-surface 

two  times. 
To  double  the  quantity  of  water  flowing  through  a  pipe  under  a  given 

head  requires  eight  times  the  power. 
27  154  inches  of  water  will  spread  i  inch  deep  over  i  acre  of  ground, 

and  weigh  101  tons. 

A  foot-pound  of  work  is  the  expenditure  of  power  required  to  raise 
one  pound  one  foot  high  in  one  minute. 

A  horse-power  is  33,000  foot-pounds,  or  what  a  strong  horse  can  do 
10  hours  daily  every  minute  in  the  day. 
Average  horses  can  do  but  22,000  ft. -Ibs 
per  minute. 

To  find  the  horse-power  required  to  raise  water:  Multiply  the 
number  of  pounds  of  water  to  be  raised  per  minute  by  the  height  from 
the  level  of  the  water  to  the  level  of  discharge  and  divide  by  33,000. 


372 


GOLD  TABLE  AND   HYDRAULICS 


TABLES   FOR   CALCULATING   THE    HORSE-POWER  OF 
WATER. 

MINERS'-INCH    TABLE. 

The  following  table  gives  the  horse-power  of  one  miners'  inch 
of  water  under  heads  from  one  up  to  eleven  hundred  feet.  This 
inch  equals  i%  cubic  feet  per  minute. 


Head  in  Feet. 

Horse-power. 

Head  in  Feet. 

Horse-power. 

I 

.0024147 

320 

.772704 

20 

.0482294 

330 

.796851 

30 

.072441 

340 

.820998 

40 

.096588 

350 

.845145 

50 

•120735 

360 

.869292 

60 

.144882 

370 

•893439 

70 

.  169029 

380 

.917586 

80 

.193176 

390 

•941733 

90 

.217323 

400 

.965880 

100 

.241470 

410 

.990027 

no 

.265617 

420 

.014174 

120 

.289764 

430 

•038321 

130 

•3I39II 

440 

.062468 

140 

.338058 

450 

.086615 

150 

.362205 

460 

.110762 

1  60 

•386352 

470 

•  134909 

170 

.410499 

480 

.I59056 

180 

.434646 

49° 

.  183206 

190 

.458793 

500 

.207350 

200 

.482940 

520 

•255644 

2IO 

.507087 

540 

•303938 

22O 

•531234 

560 

.352232 

230 

.555381 

580 

.400526 

240 

.579528 

600 

.448820 

250 

.603675 

650 

•569555 

260 

.627822 

700 

.  690290 

270 

.651969 

750 

.811025 

280 

.676116 

800 

.931760 

290 

.  700263 

900 

2.173230 

300 

.724410 

1000 

2.414700 

310 

•748557 

1  100 

2.656170 

WHEN    THE    EXACT    HEAD    IS    FOUND    IN    ABOVE    TABLE. 

Example. — Have  loo-foot  head  and  50  inches  of  water.  How 
many  horse-power? 

By  reference  to  above  table  the  horse-power  of  I  inch  under 
100  feet  head  is  .241470.  This  amount  multiplied  by  the  number 
of  inches,  50,  will  give  12.07  hoise  power. 


CUBIC-FEET  TABLE 


373 


CUBIC-FEET    TABLE. 

The  following  table  gives  the  horse-power  of  one  cubic  foot  of 
water  per  minute  under  heads  from  one  up  to  eleven  hundred 
feet: 


Head  in  Feet. 

Horse-power. 

Head  in  Feet. 

Horse-  power. 

I 

.0016098 

320 

.515136 

20 

.032196 

330 

.531234 

30 

.048294 

340 

•547332 

40 

.064392 

350 

•  563430 

50 

.080490 

360 

.579528 

60 

.096588 

370 

.595626 

70 

.112686 

380 

.611724 

80 

.128784 

390 

.627822 

QO 

.144892 

400 

.643920 

100 

.160980 

410 

.660018 

no 

.177078 

420 

.676116 

120 

.193176 

430 

.692214 

130 

.209274 

440 

.708312 

140 

.225372 

450 

.724410 

150 

.241470 

460 

.740508 

160 

.257568 

470 

.756606 

170 

.273666 

480 

.772704 

1  80 

.289764 

490 

.788802 

190 

.305862 

500 

.  804900 

200 

.321960 

520 

•837096 

2IO. 

.338058 

540 

.869292 

220 

.354156 

560 

.901488 

230 

.370254 

580 

•933684 

240 

.386352 

600 

.965880 

250 

.402450 

650 

•046370 

260 

.418548 

700 

.126860 

270 

.434646 

750 

.207350 

280 

.450744 

800 

.287840 

290 

.466842 

900 

.448820 

300 

.482940 

IOOO 

.609800 

310 

.499038 

IIOO 

.770780 

WHEN    EXACT    HEAD    IS    NOT    FOUND    IN    TABLE. 

Take  the  horse-power  of  i  inch  under  i-foot  head  and  multiply 
by  the  number  of  inches,  and  then  by  number  of  feet  head.  The 
product  will  be  the  required  horse-power. 

Note. — The  above  formula  will  answer  for  the  cubic-feet  table, 
by  substituting  the  equivalents  therein  for  those  of  miners' 
inches. 

Horse-power  given  in  above  table  equal  85  per  cent  of  theoretical 
power. 


374  GOLD  TABLE  AND  HYDRAULICS 


FLOW  OF  WATER    THROUGH  CLEAN  IRON 

PIPES. 

Remarks.  —  In  the  analysis  of  the  flow  of  water,  the 
total  head  is  divided  into  three  parts, :  viz.,  ist,  that  por- 
tion of  the  head  due  to  the  velocity;  2d,  that  portion 
which  overcomes  the  resistance  of  entry;  and  3d,  that 
portion  which  overcomes  the  resistance  within  the  pipe. 
In  long  pipes,  the  two  former  portions  as  compared  with 
the  latter  portion  of  the  total  head  are  quite  small.  In 
this  table  the  greatest  velocity  in  any  pipe  is  13.445  feet 
per  second,  due  to  4.2  feet,  the  sum  of  the  first  and  second 
portions  of  the  total  head,  while  the  third  portion  of  the 
head  is  211.2  feet.  The  head  or  fall  in  this  table  refers 
to  the  third  portion  of  the  total  head.  This  table  has 
been  computed  on  the  assumption  that  the  length  of  any 
pipe  is  not  less  than  1000  times  its  diameter. 

Question:  The  fall  being  52.8  feet  per  mile,  what  will 
be  the  flow  through  a  pipe  22  inches  diameter,  in  cubic 
feet,  also  in  miner's  inches? 

Answer:  In  this  table  find  in  first  column  52.8  feet, 
opposite  which  in  column  headed  22  Inches  will  be 
found  the  required  quantity,  viz.,  21.06  cubic  feet,  which 
multiplied  by  50  gives  1053  miner's  inches. 

Question :  The  diameter  of  the  pipe  being  24  inches, 
what  fall  will  be  required  for  the  pipe  to  carry  1000 
miner's  inches? 

Answer:  In  this  table,  in  column  headed  24  Inches, 
find  that  number  which  multiplied  by  50  will  make 
the  1000  miner's  inches  given.  In  this  case  the  nearest 


FLOW  THROUGH  PIPES  375 

number  is  20.42,  opposite  which  in  column  headed 
Fall  per  Mile  will  be  found  31.68  feet,  the  fall  required. 

Question:  In  carrying  1050  inches  of  water  to  a 
hydraulic  mine  in  a  pipe  27  inches  diameter,  having  a 
fall  of  95.04  feet  to  the  mile,  what  will  be  the  effective 
head  at  the  mine  ? 

Answer:  In  this  table,  in  column  headed  27  Inches, 
find  that  number  which  multiplied  by  50  will  make 
1050  approximate  miner's  inches.  In  this  case  we 
have  21.13  cubic  feet,  opposite  which  in  column  headed 
Fall  per  Mile  we  find  18.48  feet,  which  is  the  head  per 
mile  lost  in  carrying  the  water.  Subtracting  this  from 
the  given  fall  or  head  gives  the  effective  head.  Thus 
95.04  —  18.48  =  76.56  feet  effective  head. 

Question :  There  being  7.5  gallons  in  a  cubic  foot, 
and  86,400  seconds  in  a  day  (twenty-four  hours),  the 
fall  7.39  feet  per  mile,  how  many  gallons  will  a  pipe 
40  inches  diameter  carry  per  day? 

Answer:  In  this  table,  in  column  headed  40  Inches 
and  opposite  7.39  feet  headed  Fall  per  Mile,  will  be 
found  37.57  cubic  feet  flow  per  second.  Then  37.57 
X  7.5  X  86,400  =  24,345,360  gallons. 

GENERAL  RULE.  —  The  velocity  per  second  is  equal 
to  50  times  the  square  root  of  the  product  of  the  head 
and  diameter  in  feet,  divided  by  the  sum  of  the  length 
and  50  times  the  diameter  of  the  pipe  in  feet. 

SHORT  PIPES.  —  This  rule  applies  to  both  long  and 
short  pipes,  and  is  approximately  accurate  if  the  diame- 
ter does  not  exceed  two  feet. 


376 


GOLD  TABLE  AND   HYDRAULICS 


TABLE    SHOWING    FLOW    OF    WATER    PER    SECOND    THROUGH 
CLEAN    IRON    PIPES. 


Diameters. 

Fall 

Fall 

Per  Mile. 

Per  Rod. 

Feet. 

Ft.     In. 

Mfe 

Kin. 

i  in. 

i^in. 

i%in. 

2  in. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

21  .  12 

o  0.792 

.02584 

26.40 

On  QQO 

.02014 

.02924 

31.68 

V'W'-' 

o   .188 

.01460 

.02270 

O^27J. 

•jfi  06 

o   ^06 

.oi«?8^ 

.02426 

vfjf»m 

O'1AQ2 

j"*-  yw 

42.24 

v   •  jyj 

o   .584 

.00567 

•  \j  j.  3<J^ 
.01707 

.02638 

.VJ^^VJ^ 

.03776 

A*l  H2 

o   .  782 

.  006  I  7 

.Ol8l6 

.02838 

.O4O8l 

4/*  j^ 
52.80 

o   .980 

.00316 

.00677 

.01963 

.02988 

.04321 

63.36 

o  2.376 

.00122 

.00350 

.00781 

.02123 

.03260 

.04843 

73-92 

o  2.772 

.00124 

.00377 

.00841 

.O2282 

.03556 

.05150 

84-48 

o  3.168 

.00135 

.00411 

.00886 

.02466 

.03706 

.05456 

95.04 

o  3-564 

.00143 

.00445 

.00961 

.02577 

•03923 

.05740 

105.60 

o  3.960 

.OOI5O 

.00466 

.00990 

•02793 

.04224 

.06lII 

158.40 

o  5.940 

.00197 

.00589 

.01245 

.03458 

.05175 

.07399 

211.20 

o  7.920 

.OO24I 

.00705 

.01492 

-04132 

.06167 

.08734 

264.00 

o  9.900 

.00279 

.00798 

.01666 

•04577 

.07145 

.1095 

316.80 

o  11.880 

.00315 

.00874 

.01857 

.05043 

.07830 

.I2OO 

369.60 

1.86 

.00340 

.00951 

.01988 

.05424 

.08381 

.1288 

422.40 

3.84 

.00366 

.01012 

.02141 

.05804 

.08949 

•1375 

475.20 

5.82 

.00389 

.01086 

.02283 

.06191 

.09400 

.1442 

5  28  oo 

7.80 

.00410 

.01144 

.02424 

.06724 

.10030 

.1523 

633.00 

11.76 

•00453 

.01282 

.02676 

.07400 

.1110 

.1634 

739.20 

2  3-72 

.00473 

.01380 

02890 

.O8O2O 

.1200 

.1748 

844.00 

2  7.68 

.00524 

.01480 

.03081 

.08622 

.1285 

.T855 

950.40 

2  11.64 

•00559 

.01567 

.03276 

.09225 

.1372 

.1955 

1056.00 

3  3.6o 

.00589 

.01656 

.03458 

.09692 

.1450 

.2047 

1320.00 

4  1.50 

.00660 

.01871 

.03897 

.1079 

.1617 

.2276 

1584.00 

4  11.40 

.00732 

.02064 

.04316 

.1187 

•1773 

.2483 

2112.00 

6  7.20 

.00855 

.02390 

.04987 

.1380 

.2050 

.2833 

2640.00 

8  3.00 

.00966 

O27OH 

.05648 

I  ^sO 

3l68.OO 

9  10.80 

.01065 

,<J^/U5 
O7OO^ 

.06320 

.  O3'-' 

3696.00 

I  I  6.60 

.OII56 

•vy*%j 

0^701 

060.4.^ 

4224.  oo 

T  -7    2  J.O 

.01248 

•^j  jwi 

O-3C72 

•*-"jy4j 

47  e  2  OO 

L  j   ••  V 

14  10.  20 

01  ^^8 

•^jo  I  *• 
.03786 

H-  /  0  ^  •  \J\-f 

5280.00 

16  5.00 

•ui  jjv 
.01419 

FLOW  OF  WATER 


377 


TABLE    SHOWING    FLOW    OF    WATER    PER    SECOND    THROUGH 
CLEAN    IRON    PIPES. 


Fall 
Per  Mile. 
Feet. 

Fall 
Per  Rod. 
Ft.   In. 

Diameters. 

3  in. 
Cu.  Ft 

4  in. 
Cu.  Ft. 

6  in. 
Cu.  Ft. 

8  in. 
Cu.  Ft. 

10  in. 
Cu.  Ft 

ii  in. 
Cu.  Ft. 

12  in 
Cu.  Ft. 

5.280 
6.336 
7.392 
8.448 
9.504 
10.560 
11.616 
12.672 
13-728 
14.784 
15.840 
18.480 

21.120 
26.400 
31.680 
36.960 
42.240 
47.520 
52.800 
63.360 
73-920 
84.480 
95.040 
IO5.6OO 
158.400 
211.  2OO 
264.OOO 
316.800 
369.000 
422.400 
475-200 
528.000 
633.600 
739-200 
844.800 
950.400 
1056.000 
1320.000 
1584.000 

0  0.198 
o  0.238 
o  0.277 
o  0.317 
o  0.356 
o  0.396 
o  0.436 
o  0.475 
o  0.515 
o  0.554 
o  0.594 
o  0.684 
o  0.792 
o  0.990 
o  1.188 
o  1.386 
o  1.584 
o  1.782 
o  1.980 
o  2.376 
o  2.772 
o  3.168 
o  3-564 
o  3.960 
o  5  .940 
o  7.920 
o  9.900 

0  II.  880 

i  1.860 
i  3.840 
i  5.820 
i  7.800 
i  11.760 

2   3.720 
2   7.680 
2  11.640 

3  3.600 
4  1-500 
4  11.400 

.265 
.402 
.489 

•634 
.728 
.826 
.940 
2.O26 
2.I.I7 
2.2O7 
2.297 
2.466 
2.662 
3.020 
3.310 
3.601 
3.856 
4.072 
4.305 
4-728 
5-094 
5.482 
5  839 
6.160 
7-630 
8.860 
9.967 

.878 
.960 

.047 
.110 

.194 
.265 
.325 
.377 
.423 
.470 

.587 
.683 
.865 
2.059 

2.222 

2.383 
2.514 
2.662 
2.932 
3-210 
3-450 
3.679 
3.856 
4.762 
5.563 
6.704 

.120 
.221 
.320 

•394 
.490 

.580 

.653 
.722 

.788 

.854 
.996 
2.136 

2-397 
2.636 
2.858 
3.062 
3-232 
3.4I9 
3.76o 
4.016 
4-390 
4.679 
5-251 
6.086 
7.022 
8.244 

.573 
.611 

•639 
.659 
•703 
.737 
.768 
.808 
.876 
•931 
.045 
•  575 
.262 

•344 
.424 
.496 
.644 
.782 
.916 
2.033 

2.155 
2.667 

3-145 
3.513 
3.847 
4.196 

.298 
.314 
.330 
.346 
•359 
•  377 
•395 
•444 
.496 
.548 
.589 
.631 
.672 
.721 

.784 
.858 
.922 
•975 
.022 
.263 
.484 
.665 
.929 
.976 
2.144 
2.274 
2-399 

.1235 
.1298 

.1335 
.1465 
.1562 
.1771 
.1923 
.2146 

•2339 
.2460 
.2582 
.2893 
.3036 
.3237 
.3412 
.3607 
.4503 
•5331 
•5954 
.6390 
.6967 
.7506 
.7960 

•9464 
.9270 
I.  0060 
1.0810 

.0630 
.0692 
.0749 
.0839 
.0915 
.0992 
.1060 
.1119 
.1190 
.1313 
.1413 
.1507 
.1590 
.1717 
.2081 
.2469 
.2785 
.3049 
•3331 
•3559 
.3816 

.4043 
.4440 

•4977 
.5131 
.5436 
.5832 
.6523 

378 


GOLD  TABLE  AND  HYDRAULICS 


TABLE    SHOWING    FLOW    OF    WATER    PER    SECOND    THROUGH 

CLEAN  IRON  PIPES — (continued.) 


Diameters. 

Fall 

Fall 

per 

per 

Mile. 

Rod. 

14  In. 

15  In. 

i6ln. 

i8ln. 

20  In. 

22  In. 

24  In. 

27  In. 

Feet 

Ft.    In. 

X1  ecu 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  ft. 

Cu.Ft. 

2.  1  1 

o   0.08 

2  64 

O    O.  IO 

8  27 

A.VI.T 

•j  17 

O    O.I2 

3.6l 

4.6l 

6.10 

w.  A  y 

8.37 

J°      1 

3.  70 

o  0.14 

2.25 

<3    JO 

Jt\J  L 
4  .07 

tf..  \J  a. 

6  64 

w-  ^  / 

Q  oo 

4.22 

o  o.-i6 

1.71 

2.05 

2-43 

j.  i*J 
3.27 

,\J  j 
4-35 

5*62 

W.  V*-|, 

7.13 

V-'-'V 

9.48 

4.75 

o  o  18 

1.83 

2.19 

2-59 

3-49 

4-68 

6.01 

7.56 

10.26 

5.28 

O    O.2O 

1.91 

2.30 

2.72 

3-66 

4.92 

6.32 

7.95 

10.74 

5.81 

0    0.22 

2.02 

2.43 

2.88 

3-88 

5-15 

6.62 

8.34 

11-45 

6.34 

o  0.24 

2.  II 

2.54 

3.02 

4.06 

5.40 

6.94 

8.75 

"•93 

6.86 

o  0.26 

2,18 

2.65 

3.18 

4-23 

5-62 

7.24 

9.14 

12.54 

7-39 

o  0,28 

2.27 

2.75 

3.28 

4.40 

5-82 

9-47 

12.96 

7.92 

o  0.30 

2.35 

2.84 

3-39 

4.61 

6,05 

£78 

9.80 

J3-49 

8-45 

o  0.32 

2-44 

2-94 

3-49 

4-75 

6.27 

8.03 

10.13 

13-98 

8.98 

o  0.34 

2.54 

2.98 

3.62 

4.90 

6.48 

8.36 

10-57 

14.41 

9-50 

o  0.36 

2.59 

3-II 

3.69 

5-03 

6.65 

8.55 

10.77 

14.81 

10.03 

o  0.38 

2.67 

3.21 

3.8i 

5-17 

6.92 

8.85 

II.  IO 

15.21 

10.56 

o  0.40 

2.72 

3.29 

3.92 

5.30 

7.05 

9.07 

11-43 

15-63 

11.62 

o  0.44 

2.88 

3-47 

4.12 

5.63 

7.42 

9-55 

12.05 

16.44 

12.67 

o  0.48 

3.02 

3-63 

4.32 

5-87 

7-79 

10.01 

12.  OI 

I7  23 

13-73 

o  0.51 

3-15 

3-79 

4-51 

6.18 

8.14 

10.48 

13.23 

18.01 

14-78 

o  0.55 

3.29 

3-95 

4.68 

6.38 

8.48 

10.91 

13.79 

18.75 

15.84 

o  0.59 

3-42 

4.11 

4.87 

6.64 

8.77 

11.29 

14-25 

19.50 

18.48 

o  0.69 

3.62 

4.46 

5.31 

7-17 

9-49 

12.25 

15-50 

21.13 

21.12 

o  0.79 

3.99 

4.78 

5.67 

7.65 

10.16 

13.12 

16.62 

22.62 

26.40 

o  0.99 

4-46 

5-37 

6-39 

8.66 

ii-43 

14.78 

18.71 

25.34 

31.68 

o     .19 

4.91 

5.91 

7.02 

9-54 

12.59 

16:20 

20.42 

27.74 

36.96 

o     .39 

5-37 

6.45 

7.66 

10.33 

13-66 

17.53 

22.05 

29.96 

42.24 

o     .59 

5.77 

6.90 

8.16 

11.09 

14.66 

18.78 

23.61 

31-99 

47.52 

o     .78 

6.  ii 

7-31 

8.64 

11.71 

15.54 

19-93 

25.07 

33-97 

52.80 

o     .98 

6.44 

7-70 

9.10 

12-37 

16.47 

21.  06 

26.42 

35.89 

63.36 

o  2.38 

7.00 

8.39 

9-95 

13-65 

17.99 

23.07 

29.03 

39.76 

73.92 

o  2.77 

7.60 

9.15 

10.87 

14.75 

19-49 

24.68 

31.49 

43-22 

84.48 

o  3.17 

8.17 

9.81 

11.63 

15-84 

21.03 

26.97 

33.90 

46.57 

95-04 

o  3-56 

8-93 

10.47 

12.43 

16.90 

22.45 

29.70 

36.18 

48.06 

IO5.6O 

0     -i  06 

9.26 

1  1.09 

j  /»     ,    . 

17.85 

o  Q     rf\ 

•J  I    1C 

oft    <  r 

158.40 

u    j.yw 

Of    Ql 

j  j    og 

13*66 

16.  17 

21.86 

28.86 

J  1«  *  D 

211.20 

D-VH 

o  7.92 

13.22 

15.84 

18.77 

FLOW  OF  WATER 


379 


TABLE    SHOWING    FLOW    OF   WATER    PER   SECOND    THROUGH 

CLEAN  IRON  PIPES — (continued?) 


Diameters. 

Fall 
per 
Mile. 

Fall  per 
Rod. 

30  In. 

33  In. 

36  In. 

40  In. 

44  In. 

48  In. 

Feet: 

Ft.    In. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

1.  06 

o    0.04 

IO.2Q 

13.88 

181 

22  08 

1.58 

o    0.06 

7.78 

IO.2I 

AVX.AIV^ 
12.70 

*  J*  ww 

17.00 

22.22 

•vu 

27.89 

2.  1  1 

o    0.08 

8-99 

11.65 

14.56 

19.68 

25-55 

32.93 

2.64 

0      0.10 

10.24 

12.92 

16.35 

22.08 

28.87 

37-00 

3.17 

O      0.  12 

10.97 

13.99 

18.02 

24-43 

31.46 

40.21 

3.70 

o    0.14 

11.90 

15.14 

19.76 

26.27 

34-47 

43.67 

4.22 

0      O.l6 

12.84 

16.36 

20.85 

28.14 

37-05 

46.81 

4-75 

o    o.i  8 

13.48 

17.58 

22.30 

29.80 

39.01 

49.06 

5.28 

O      O.2O 

14.21 

18.74 

23.47 

31.46 

41.06 

52.15 

5-8i 

0      0.22 

15.05 

19-54 

24.91 

33-25 

42.09 

54-95 

6  34 

o    0.24 

I5.8I 

20.28 

26.12 

34-68 

44-97 

57.36 

6.86 

0      0.26 

16.47 

21.29 

27.20 

36.21 

46.77 

60.07 

7-39 

o     0.28 

17.18 

22.2O 

28.24 

37-57 

48.83 

62.O2 

7.92 

o    0.30 

17.94 

23.01 

29.19 

39-18 

50.62 

64.47 

8-45 

o    0.32 

18.58 

23.76 

30.29 

40.54 

52.46 

66.53 

8.98 

o    0.34 

19.21 

24.47 

41.88 

54-04 

68.50 

9.50 

o    0.36 

19.66 

25.22 

32.48 

43-07 

55.48 

70.62 

10.03 

o    0.38 

20.32 

26.14 

33.40 

44.28 

57-01 

72.75 

10.56 

o    0.40 

20.79 

26.94 

34.49 

45.20 

58.85 

74-44 

11.62 

o    0.44 

21.  80 

28.27 

36.15 

48.12 

61.71 

78.29 

12.67 

o    0.48 

22.83 

29.02 

37.74 

50.48 

64.35 

81.68 

13.73 

o     0.51 

23-93 

31.06 

39-40 

52.67 

66.87 

85.20 

14.78 

o    0.55 

24.86 

32.28 

40.86 

55.04 

69.57 

88.46 

15.84 

o    0.59 

25.87 

33.62 

42.28 

56.33 

72.32 

9L73 

18.48 

o    0.69 

27.96 

36.17 

45.95 

61.09 

77-95 

100.40 

21.12 

o    0.79 

29.84 

38.57 

48.83 

65.41 

83.60 

105.89 

26.40 

o    0.99 

33.55 

43.12 

54.89 

73-09 

93-37 

119-34 

31-68 

o     1.19 

36.79 

47.40 

59-95 

80.32 

103.28 

130.88 

36.96 

o     1.39 

39-66 

5L35 

65.17 

86.70 

111.74 

148.09 

42.24 

o     1.59 

42.39 

54-91 

69.80 

92.58 

II9-93 

153-94 

47.52 

o    1.78 

45.2*? 

r  Q    Aft 

74.-3-I 

08.00 

128.26 

52.8O 

**         **/** 

o     i.  08 

*rD*     J 
47.71 

6i!62 

/  *T-  o  j 
78.46 

yvj.v 

63.36 

*  *  V 

o    2.38 

*T/  *  /  * 

52.91 

68.00 

y  w.  t|.vr 

82.84 

73.92 

o    2.77 

73-95 

GOLD  TABLE  AND    HYDRAULICS 


TABLE    SHOWING    FLOW    OF   WATER    PER   SECOND    THROUGH 

CLEAN  IRON  PIPES — (continued?) 


Fall  Per 

Fall  Per 

Diameters. 

Mi(e. 
Feet. 

Rod. 
Ft.      In. 

54  In. 
Cu.  Ft. 

60  In. 
Cu.  Ft. 

72  In. 
Cu.  Ft. 

84  In. 
Cu.  Ft. 

96  In. 
Cu.  Ft. 

•53 

0     0.02 

21.96 

29.77 

46.99 

75-43 

107.77 

i.  06 

o    0.04 

31.70 

38.19 

57.65 

104.61 

152.45 

1.58 

o    0.06 

38.53 

52.09 

82.53 

126.18 

188.45 

2.  1  1 

o    0.08 

45-12 

59-°4 

95-99 

145.43 

218.75 

2.64 

O      O.IO 

50.23 

67-56 

109.42 

162.75 

245.30 

3-17 

0      0.12 

55-51 

74.32 

121.58 

177.03 

267.41 

3-70 

o    0.14 

60.21 

80.51 

132.04 

192.04 

290.53 

4.22 

o    0.16 

63.61 

86.30 

139.96 

207.81 

310.89 

4-75 

o    0.18 

67.20 

91.99 

148.72 

222.44 

324.20 

5-28 

0      0.20 

72-37 

96.98 

157.77 

235.13 

350.45 

5.81 

0      0.22 

75.71 

102.39 

165.97 

253.34 

366.19 

6.34 

o    0.24 

79-  *3 

107.31 

173.04 

264.77 

382.02 

6.86 

0      0.26 

82.54 

H5.53 

179.26 

275.16 

397.85 

7-39 

0      0.28 

85.9° 

II6-53 

187.46 

287.67 

414.70 

7.92 

o    0.30 

89.52 

119.68 

193.93 

296.37 

427.76 

8.45 

o    0.32 

92.43 

123.70 

200.18 

307.87 

443.09 

8.98 

o    0.34 

95-35 

127.63 

206.40 

316.15 

457-42 

9-50 

o    0.36 

97.65 

131.26 

212.05 

326.73 

470-49 

10.03 

c     0.38 

100.19 

134-79 

217.71 

335-79 

481.53 

10.56 

o    0.40 

103.82 

138.84 

225.21 

348.25 

496.37 

11.62 

o    0.44 

108.78 

145.98 

235.52 

364.92 

522.76 

12.67 

o    0.48 

113-47 

152.56 

246.41 

389.09 

547.88 

13.73 

o    0.51 

118.48 

15865 

256.17 

394.43 

510.01 

14.78 

o     0.55 

123.10 

164.54 

267.19 

408.36 

592.13 

15.84 

o    0.59 

128.19 

170.43 

277.88 

423.36 

612.00 

18.48 

o    0.60 

1^8.02 

181  08 

2QQ  72 

482  QQ 

AW»^V 

21.12 

v.wy 
O     0.  7Q 

•*•  «ju.  V 
147.  QI 

1  "j*  Vw 
IO7.C2 

•*W"  tm 
02O.74 

4**«  .yy 

26.40 

*  /  V 
O      O.QQ 

A4T  /  *V  *• 
I65.8O 

*V  /   j 
221.  (X 

J"*J°  /^T 

•^8.52 

31.68 

w 

O       I.IQ 

182.42 

mmm  *^j 
244.26 

O  D  w*  3* 

36.96 

if 

O       I.^Q 

I9O.OI 

j  v«  *y*s 

*«?V 

ANGULAR  BENDS  381 

RELATION  OF  CLEAN,  SLIGHTLY  ROUGH,  AND  VERY 
ROUGH  PIPES  WITH  RESPECT  TO  THEIR  CARRYING 
CAPACITY. 

CLEAN  PIPES.  —  The  tables,  as  appear  by  the  head- 
ings, have  been  computed  for  clean  pipes,  in  other 
words,  smooth  and  straight. 

SLIGHTLY  ROUGH  PIPES.  —  When  the  pipe  is  slightly 
rough,  multiply  the  tabulated  number  for  clean  pipes  by 
the  decimal  .886  to  determine  its  carrying  capacity. 

VERY  ROUGH  PIPES.  —  If  the  pipe  is  'very  rough, 
multiply  the  tabulated  number  for  clean  pipes  by  the 
decimal  .773  to  determine  its  carrying  capacity. 

RELATION  OF  THE  INLET  FORMS  OF  PIPES  WITH  RE- 
SPECT TO  THE  COEFFICIENTS  OF  ENTRANCE. 

COEFFICIENTS.  —  Of  the  three  following  forms,  viz., 
Bell-mouthed,  Square- edged,  and  Square- edged  pro- 
jecting into  the  reservoir,  their  coefficients  will  be  in 
order  .900,  .836,  and  .734. 

ANGULAR  BENDS  AND  TABLE. 
ADDITIONAL   HEAD   REQUIRED   TO   OVERCOME    ONE 

ANGULAR  BEND. 

Question :  The  velocity  being  40  feet  per  second, 
what  additional  head  is  required  to  overcome  the  resist- 
ance of  an  angular  bend  whose  angle  of  deflection  is  90 
degrees  ? 


382 


GOLD  TABLE  AND  HYDRAULICS 


Answer:  In  this  table  find,  in  column  headed  Velo- 
city per  Second,  40,  opposite  which,  in  column  headed 
90°  Heady  will  be  found  24.45  feet>  tne  additional 
head  required. 

TABLE  SHOWING  ADDITIONAL  HEAD  REQUIRED  TO 
OVERCOME  THE  RESISTANCE  OF  ONE  ANGULAR 
BEND. 


Veloc- 

Angles of  Deflection. 

ity 

per  Sec- 

ond. 

i5°Head. 

30°  Head. 

40°  Head. 

60°  Head. 

90°  Head. 

i2o°Head. 

Feet. 

Feet. 

Feet. 

Feet. 

Feet. 

Feet. 

Feet. 

i 

.0002 

.0005 

.002 

.006 

.015 

.029 

2 

.0010 

.0019 

.009 

.023 

.061 

.116 

3 

.0022 

.0042 

.019 

.051 

•138 

.260 

4 

.004 

.008 

•035 

.090 

•  245 

.462 

5 

.006 

.012 

•  054 

.141 

.382 

•723 

6 

.009 

.017 

.078 

.204 

•550 

1.04 

7 

.012 

.023 

.106 

.277 

•749 

1.42 

8 

.Ol6 

.030 

.138 

.362 

.978 

1-85 

10 

.025 

.047 

.216 

.565 

I-53 

2.89 

IS 

.056 

.105 

.486 

1.27 

3-44 

6.50 

20 

.099 

.186 

.863 

2.26 

4.85 

11.56 

25 

•155 

.291 

i-35 

4-45 

9-55 

18.06 

3° 

.224 

.419 

1.94 

5-09 

13-75 

26.01 

40 

.398 

•745 

3-45 

9.04 

24.45 

46.23 

5° 

.621 

1.17 

5-40 

14-13 

38.20 

73-93 

75 

1.40 

2.62 

12.14 

31-79 

85-95 

162.5 

100 

2.48 

4.66 

21.58 

56-52 

152.8 

289.0 

iS° 

5-59 

10.48 

48.57 

127.2 

343-7 

650.2 

200 

9.94 

18.63 

86.32 

226.  i 

611.1 

1156. 

300 

22.36 

41.92 

194.20 

508.7 

1092. 

2601. 

ADDITIONAL    HEAD    NECESSARY    TO    OVERCOME   THE 
RESISTANCE  OF  ONE  CIRCULAR  BEND. 

Question:  The  radius  of  the  pipe  being  to  the  radius 
of  the  bend  in  the  ratio  of  1:5,  the  number  of  degrees 


OPEN  CHANNELS  383 

in  the  bend  being  90  degrees,  and  the  velocity  75  feet  per 
second,  what  is  the  additional  head  required  to  overcome 
the  resistance  of  the  bend  ? 

Answer:  In  this  table,  in  first  column,  headed 
Velocity  per  Second,  find  75  feet,  opposite  which, 
in  column  headed  1:5,  90°,  is  found  6.03  feet,  the 
required  head. 

Question :  The  radius  of  the  pipe  being  to  the  radius 
of  the  bend  in  the  ratio  of  2:5,  the  number  of  degrees 
in  the  bend  being  1 20  degrees,  and  the  velocity  per  second 
100  feet,  what  is  the  additional  head  required  to  over- 
come the  resistance  of  one  bend  ? 

Answer:  In  this  table,  opposite  100  feet  velocity, 
will  be  found  in  column  headed  2:5,  120°,  the  re- 
quired number,  viz.,  21.34  feet. 

RELATIVE  CARRYING  CAPACITY  OF  OPEN  CHANNELS 
WHOSE    SECTIONAL   AREAS    ARE    EQUAL   TO    EACH 

OTHER  BUT  OF  DIFFERENT  FORMS. 

The  form  in  which  the  bottom  width  is  made  equal 
to  one  of  the  sides,  and  in  which  the  base  to  the  perpen- 
dicular of  the  side  slope  is  as  3  : 4,  has  been  adopted 
as  the  standard  form  when  the  ground  will  admit,  it 
being  the  simplest  of  construction. 

The  relative  carrying  capacity  for  trapezoidal  form  — 
Base :  depth  of  slope  1:3:4;  bottom  width :  depth : :  5  .-4. 
Coefficient  of  capacity,  1000. 

Trapezoidal  form  —  Base  :  depth  of  slope  :  :  i  :  i ; 
bottom  width  =  depth,  .994. 

Coefficients:  flume,  2:1,  .961;  semi- hexagonal,  1.008; 
square,  .925;  semicircular,  1.056. 


384  GOLD  TABLE  AND  HYDRAULICS 

Question:  The  fall  being  6  feet  per  mile,  the  sectional 
area  of  a  square  flume  8  square  feet,  what  will  be  its 
carrying  capacity  per  second? 

Answer:  In  table  showing  Flow  of  Water  in  Open 
Channels  —  Base  to  Perpendicular  of  Side  Slopes  being 
as  3  :  4,  in  column  of  Fall  per  Mile,  find  the  given 
fall  6  feet,  opposite  which  in  column  headed  sectn. 
8. o  square  feet  is  found  13.65  cubic  feet.  This  multi- 
plied by  the  coefficient  for  a  square,  viz.,  .925,  gives 
13.64  X  .925  =  12.63  cubic  feet. 

Remarks.  —  The  tables  for  the  flow  of  water  in  open 
channels  have  been  computed  upon  the  assumption 
that  the  canals  are  smooth  and  straight. 


FLOW  OF  WATER  THROUGH  NOZZLES. 

Question:  The  head  being  125  feet,  how  many  cubic 
feet  per  second  will  a  nozzle  4  inches  in  diameter  dis- 
charge? How  many  miners'  inches? 

Answer:  In  this  table  find  in  the  first  column  the 
given  head,  125  feet,  opposite  which,  in  column 
headed  4  Inches,  will  be  found  the  required  quantity, 
viz.,  7.28  cubic  feet  X  50  =  364  miner's  inches. 

Question:  Between  the  inlet  and  the  nozzles  of  a 
hydraulic  pipe  3  feet  in  diameter  the  distance  is  five 
miles  and  the  total  fall  275  feet.  The  pipe  is  to  carry 
2000  miners'  inches  of  water,  which  is  to  be  discharged 
through  two  "  Little  Giants,"  or  nozzles  equal  in  size. 
What  will  be  the  loss  of  head  by  the  resistance  in  the 
main  pipe?  What  will  be  the  size  of  each  nozzle? 

Answer:  In  table  showing  Flow  of  Water  Through 


FLOW  THROUGH  NOZZLES  385 

Clean  Iron  Pipes  find  in  column  headed  36  Inches  that 
number  which  multiplied  by  50  will  make  2000,  the 
given  number  of  miner's  inches.  In  this  case  40.86 
approximates  sufficiently  near,  opposite  which,  in  column, 
headed  Fall  per  Mile,  is  found  14.78  feet,  the  loss 
of  head  per  mile.  Multiply  this  by  5,  the  length  of  the 
pipe,  and  we  have  14.78  X  5  =  73.9  feet,  the  loss  of 
resistance  in  the  pipe  5  miles  long.  Subtracting  this 
from  the  total  head,  275  —  73.9  =  201.1  feet  remaining 
head.  Again,  in  the  table  find  200  nearest  201.1  feet 
in  column  headed  Head,  opposite  which,  in  column, 
headed  6  Inches,  is  found  20.64,  which  multiplied 
by  50  gives  1.032,  or  approximately  1000  miner's  inches, 
which  each  nozzle  is  required  to  discharge.  Hence  the 
nozzles  are  to  be  6  inches  in  diameter  each. 


386 


GOLD  TABLE  AND  HYDRAULICS 


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FLOW   OF  WATER   IN  OPEN  CHANNELS 


387 


FLOW  OF  WATER    IN    OPEN  CHANNELS. 

Question  :  The  dimensions  of  a  canal  being,  top  width  n  feet, 
bottom  width  5  feet,  depth  4  feet,  and  the  fall  per  mile  8  feet. 
Required  the  number  of  inches,  miners'  measure,  that  it  will  carry. 

Answer :  In  this  table,  in  column  headed  "  Fall  per  Mile,"  find 
8  feet,  opposite  which  in  column  headed  with  given  specifications 
(n,  5,  4)  is  found  104.8  cubic  feet,  the  flow  per  second.  This  mul- 
tiplied by  50,  the  number  of  miners'  inches  equal  to  one  cubic  foot 
flow  per  second,  gives  104.8  X  5°  =  5240  miners'  inches  required. 


TABLE    SHOWING    FLOW  OF  WATER  IN  OPEN    CHANNELS,  BAS. 
TO  PERPENDICULAR  OF  THE  SIDE  SLOPES  BEING  AS  3  :  4. 


T  2.2  ft. 

T  3.3  ft. 

T  4.4  ft. 

T  5-5  ft. 

T66ft. 

T  7.7  ft. 

T  8.8  ft. 

Fall 

Fall 

B   1.0  ft. 

D    .8  ft. 

B  1.5  ft. 

Dl.2ft. 

B  2.0  ft. 

D  1.6  ft. 

B  2.5  ft. 
D  2.0  ft. 

B  3.  oft. 

D24ft. 

B  3.5  ft. 

D  2.8  ft. 

B  4.0  ft. 
D  3.2  ft. 

Mile. 
Ft. 

per 
Rod. 
In. 

Section 
1.28 
sq.  ft. 

Section 
2.88 
sq.  ft. 

Section 
5.12 
sq.  ft. 

Section 
8.0 
sq.  ft. 

Section 
".52 
sq.  ft. 

Section 
15-68 
sq.  ft. 

Section 
20.48 
sq.  ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

I 

•0375 

•45 

1-33 

2.67 

5-57 

9-05 

13.46 

20.26 

2 

.0750 

•63 

1.88 

3-87 

7.88 

12.  80 

19.04 

28.64 

3 

.1125 

•77 

2.30 

4-74 

9-65 

I5.67 

23.32 

35-08 

4 

.I5CO 

.89 

2.65 

5-47 

11.14 

18.52 

26.93 

40.51 

5 

.1875 

.00 

2-97 

6.12 

12.46 

2O.24 

30.11 

45.30 

6 

.2250 

.09 

3-25 

6.70 

13-65 

22.17 

32.98 

49.62 

7 

.2625 

.18 

3-42 

7-24 

14.74 

23-94 

35.63 

53-58 

8 

.3000 

.26 

3-75 

7-73 

15-75 

25.60 

38.08 

57-28 

9 

•3375 

•34 

3.98 

8.21 

16.71 

27-15 

40-39 

60.76 

10 

•3750 

.41 

4-19 

8.65 

17.61 

28.62 

42-57 

64.05 

ii 

.4125 

.48 

4.40 

9.07 

18.47 

30.02 

44-55 

67.18 

12 

•  4500 

•  54 

4.60 

9.48 

19.30 

31-35 

46.64 

70.65 

13 

.4875 

.61 

4-78 

9.86 

20.08 

32.63 

48.54 

73-03 

14 

.5250 

•  67 

4.96 

10.24 

20.84 

33.87 

50.38 

75-79 

15 

.5625 

•  73 

5-14  • 

10.60 

21-57 

35-05 

52.14 

78.44 

16 

.6OOO 

•  78 

5-31 

10.94 

22.27 

36.2O 

53.86 

81.02 

17 

.6375 

.84 

5-47 

11.28 

22.96 

37.31 

55-51 

83-51 

18 

.6750 

.89 

5-63 

1  1.  60 

23.63 

38.39 

57-11 

85.93 

19 

.7125 

•94 

5-78 

11.92 

24.28 

39-44 

58.58 

88.29 

20 

.7500 

•99 

5  93 

12.23 

24.91 

40.47 

60.21 

90.58 

21 

.7875 

2.04 

6.08 

12.54 

25-53 

41.47 

61.70 

92.82 

22 

.8250 

2.09 

6.22 

12.83 

26.12 

42.45 

63.15 

95-00 

23 

.8625 

2.14 

6.36 

13.12 

26.71 

43-40 

64.57 

97.15 

24 

.QOOO 

2  18 

6.50 

13.40 

27.29 

44-34 

65.95 

99-23 

25 

•9375 

2.23 

6.63 

13.68 

27.98 

45-24 

67.32 

101.28 

In  Tables,  T  signifies  top  width;  B,  bottom  width;  D,  depth. 


388 


GOLD  TABLE  AND   HYDRAULICS 


TABLE    SHOWING    FLOW    OF    WATER    IN    OPEN    CHANNELS, 
BASE    TO    PERPENDICULAR    OF    THE    SIDE    SLOPES 

BEING  AS  3  :  4. — (continued.) 


Tg.gft. 

T  ii  ft. 

T  13.2  ft. 

T  16.4  ft. 

T  17.6  ft. 

T  19.  8  ft. 

T  22  ft. 

Fall 
per 
Mile. 

Fall 
R^d. 

B  4-5  ft. 
D  3.6  ft. 
Section 

B    5  ft. 
D   4  ft. 
Section 

B    6.0  ft. 
D   4.8  ft. 
Section 

B    7.0  ft. 
D    5.6ft. 
Section 

B    8.0  ft. 
D   6.4ft. 
Section 

B    9.0  ft. 
D    7.2  ft. 
Section 

B  10  ft. 
D    8ft. 
Section 

Ft. 

In. 

25.92 

32, 

46.09 

62.72 

81.92 

103  68 

128 

sq.  ft. 

sq.  ft. 

sq.  ft. 

sq.  ft. 

sq.  ft. 

sq.  in. 

sq.  ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

I 

•0375 

28.04 

37-1 

58.4 

96.5 

138.3 

189.2 

26l.2 

2 

.0750 

39-67 

52.4 

82.7 

136.4 

195.7 

267.6 

369.4 

3 

.1125 

48.59 

64.2 

101.4 

167.1 

239-6 

327-7 

451-3 

4 

.1500 

56.IO 

74.1 

II7.I 

192.9 

276.7 

378.4 

522.3 

5 

.1875 

62.71 

82.9 

130.9 

215.7 

309.3 

423.1 

584-0 

6 

.2250 

68.70 

90.8 

143-4 

236.3 

338.8 

463.5 

639.8 

7 

.2625 

74.19 

98.1 

154.8 

255.3 

366.0 

500.5 

691.0 

8 

.3000 

79-53 

104.8 

165.5 

272.9 

391-2 

535.1 

738.7 

9 

•3375 

84.14 

III.  I 

175-6 

289.4 

415.0 

567.6 

783.5 

10 

•3750 

88.68 

II7-I 

185.1 

305.0 

437-4 

598.2 

825.9 

ii 

.4125 

93-02 

122.9 

194.1 

3I9-9 

458.7 

613.2 

866.2 

12 

.4500 

97-15 

128.4 

202.8 

334-2 

479-1 

655.4 

925-6 

13 

.4875 

101.13 

'133  6 

211.  1 

347-8 

498.7 

682.1 

941.7 

14 

.5250 

104.94 

138.7 

2I9.O 

360.9 

517.5 

707.8 

977-2 

15 

•5625 

108.63 

I43-S 

226.6 

373-6 

535-7 

732.8 

1011.5 

16 

.6000 

112.18 

148.2 

234.1 

385-9 

553-3 

756.7 

1044.7 

17 

.6375 

115-64 

152.4 

241.3 

397-8 

570.3 

780.1 

1076.9 

18 

.6750 

118.99 

157-2 

248.3 

409-3 

586.9 

802.7 

1  108.1 

19 

.7125 

122.26 

161.5 

255-1 

420.5 

601.5 

824.8 

1138.4 

20 

.7500 

125.43 

165-7 

261.7 

431-4 

618.5 

846.1 

1168.0 

21 

.7875 

1  128.53 

169.8 

268.2 

442.0 

633.9 

867.0 

1196.8 

22 

.8250 

I3L55 

173.8 

274.5 

452.5 

648.8 

8874 

1225.0 

23 

.8625 

134.51 

177-7 

280.7 

462.9 

663.4 

907.4 

1252.6 

24 

.9000 

137.40 

181.5 

286.7 

472.6 

677.7 

926.0 

1279-5 

25 

•9375 

140.  24 

185.3 

292.6 

482.3 

691.6 

946.0 

1306.0 

In  Tables,  T  signifies  top  width;  B,  bottom  width;  D,  depth. 


FLOW  OF  WATER  IN   OPEN   CHANNELS       389 

FLOW   OF   WATER   IN    OPEN    CHANNELS—  (Continued.) 

Question :  Required  the  number  of  cubic  feet  of  water  that  will 
flow  in  a  canal  whose  top  width  is  40  feet,  bottom  width  20  feet, 
depth  5  feet,  and  whose  fall  is  2  feet  per  mile. 

Answer  :  In  this  table,  in  column  "Fall  per  Mile,"  find  2  feet, 
opposite  which  in  column  headed  with  the  given  specifications 
(40,  20,  5)  is  found  the  required  flow,  viz., 376.1  cubic  feet. 


TABLE    SHOWING    FLOW    OF    WATER    IN    OPEN    CHANNELS, 

BASE    TO    PERPENDICULAR    OF    THE    SIDE    SLOPES 

BEING    AS    2  I  1. 


T6ft. 

T9ft. 

T  12  ft. 

T  16  ft. 

T  22  ft. 

T  28  ft. 

T4oft. 

B  2ft. 

B  3  ft. 

B    4  ft. 

B6ft. 

B  10  ft. 

B  12  ft. 

B  20  ft. 

Fall 

Fall 

D  i  ft. 

D  1.5  ft. 

D      2ft. 

D  2.5  ft. 

D    3  ft. 

D   4  ft. 

D    5  ft. 

per  Mile. 

per  Rod. 

Section 

Section 

Section 

Section 

Section 

Section 

Section 

Feet. 

Feet. 

4 

9 

16 

27.5 

48 

3° 

150 

sq.  ft. 

sq.  ft. 

sq.  ft. 

sq.  ft. 

sq.  ft. 

sq.  ft. 

sq.  ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

•  5 

.01875 

1.27 

3-85 

8.63 

l8.II 

8.79 

78.2 

I88.I 

.6667 

.0250 

1.46 

4.44 

9.96 

20.91 

44-79 

90-3 

217.2 

.8333 

.03125 

1.63 

4.96 

11.14 

23.38 

50.08 

IOI.O 

242.8 

i 

•0375 

1.79 

5-44 

12.  2O 

25.61 

54-86 

no.  6 

266.0 

1.25 

.046875 

2.OO 

6.08 

13.64 

28.68 

61.32 

123.7 

297.4 

1-5 

.05625 

2.19 

6.67 

14.96 

3L34 

67.26 

135.7 

326.1 

i-75 

.065625 

2.37 

7.19 

I6.I4 

33-88 

72.57 

146.4 

351-8 

2 

.0750 

2.53 

7.69 

17.26 

36.22 

77.58 

156.5 

376.1 

2.25 

.084375 

2.68 

8.16 

18.30 

38.42 

82.29 

165.9 

399-0 

2-5 

•09375 

2.83 

8.60 

19.29 

40.50 

86.72 

174.9 

420.6 

3 

.1125 

3.10 

9.42 

21.14 

44.36 

95-00 

191.6 

460.7 

3-5 

.13125 

3-35 

10.17 

22.83 

47.91 

102.6 

207.0 

497.6 

4 

.I5OO 

3-58 

10.87 

24.41 

51.22 

109.7 

221.3 

531-9 

4-5 

.16875 

3-79 

11-54 

25.88 

54-33 

116.3 

234.7 

564.2 

5 

.1875 

4.00 

12.  l6 

27.29 

57.27 

122.7 

247.4 

594-8 

6 

.2250 

4.38 

13.31 

29.89 

62.74 

134.4 

271.0 

651.5 

7 

.2625 

4-73 

14-39 

32.29 

67.79 

145.1 

292.7 

703.6 

8 

.3000 

5-06 

15.38 

34-52 

72.43 

155.2 

312.9 

752.2 

9 

•3375 

5-37 

16.31 

36.6l 

76.83 

164.6 

33L9 

797-9 

10 

•3750 

5.66 

17.19 

38.59 

80.99 

173.5 

349-9 

841  I 

ii 

.4125 

5-93 

18.03 

40.47 

84.94 

181.9 

366.9 

882.1 

12 

•  4500 

6.20 

18.74 

42.27 

88.72 

190.1 

383.2 

921.5 

In  Tables,  T  signifies  top  width  ;  B,  bottom  width  ;  D,  depth. 


390 


GOLD  TABLE  AND  HYDRAULICS 


TABLE    SHOWING    FLOW    OF    WATER    THROUGH    NOZZLES 

QUANTITY    AND    HORSE-POWER. 


1 

|| 

•s'S 

Diameters  of  Nozzles. 

s, 

tSfc 

Head 

..0 

.  o 

1 

>5  3 

M    3 

i  Inch. 

1.5  Inches. 

2  Inches. 

2.5  Inches. 

Feet. 

Feet. 

H.P. 

8  w 

H.P. 

| 
Cubic   TT  T> 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

t 

8.025 

.106 

.212 

.041 

.0046 

.093 

.010 

.164 

.018 

-255 

.029 

1.5 

9-83 

.158 

.316 

.050 

.0085 

.in 

019 

.200 

•034 

.053 

2 

"•35 

.211 

.422 

.058 

.013 

.130 

.029 

.232 

•  052 

isto 

.082 

2-5 

12.68 

.264 

.528 

.o64 

.018 

•  145 

.041 

•  256 

.072 

.402 

-.114 

3 

13.90 

•3*7 

•634 

.061 

.024 

•159 

•054 

.284 

.096 

.44° 

.150 

3-5 
4 

15.01 
16.05 

•370 
.421 

.740 
.842 

.016 
.081 

.030 
.03 

.068 
.083 

.304 
.324 

.120 
.148 

•475 
.507 

.189 
.231 

4-5 

17.02 

•474 

.948 

.086 

.044 

.194 

.099 

•344 

.176 

.540 

•275 

17-95 
19.66 

.528 
•634 

.06 
•27 

.091 

.100 

.051 
.068 

•  205 
.224 

•"3 
•J53 

•364 
.400 

.204 
.272 

.56 
.622 

•315 
•425 

7 

21.23 

•739 

•48 

.108 

.086 

.242 

•193 

•432 

•344 

.672 

•535 

7-5 

21.98 

.702 

.III 

•095 

•250 

.214 

•444 

.380 

.697 

-595 

10 

25.38 

1.06 

.12 

.129 

.146 

.290 

.329 

.516 

•  584 

•  805 

•9T5 

12.5 

28.37 

1.32 

.64 

.144 

.204 

•  324 

.46 

•  566 

.816 

.897 

1.28 

15 

31.08 

3.18 

.158 

.269 

•355 

.505 

•632 

i.  08 

.985 

1.68 

'7-5 

33-57 

I'M 

3-70 

.170 

•339 

.383 

.782 

.680 

1.36 

.06 

2.11 

20 

35.89 

2.11 

4.22 

.182 

.414 

.410 

•931 

.728 

1.66 

.14 

2.58 

22.5 

38.07 

2.38 

4.76 

•  193 

-494 

•435 

1.  11 

•772 

1.98 

.21 

3-08 

25 

40.13 

2.64 

5-28 

.204 

.578 

.458 

1.30 

.816 

•27 

27-5 

42.08 
43-95 

2.00 
3-02 

5.80 
6.04 

.213 
.228 

.660 
.760 

.480 
.513 

1.5° 
1.71 

.852 
.912 

3^S 

•33 
•4a 

4.17 

4-75 

32.5 

45-75 

3.34 

6.68 

.232 

•857 

.522 

1.93 

.928 

3-43 

•45 

35 

47-47 

3.69 

7.38 

.241 

•958 

•542 

2.15 

•964 

3-83 

•51 

5-t>8 

40 

50.75 

4.22 

8-44 

•257 

1.17 

•579 

2.63 

.03 

4.68 

.61 

7-31 

45 

53.83 

4.75 

9.50 

.273 

1.40 

.614 

3-I4 

.09 

5-6o 

•71 

8.23 

g 

56.75 
62.16 

5.28 
6.34 

10.56 
12.68 

.288 
•385 

1.64 
2.15 

.648 
.709 

3-68 
4.84 

.'26 

6.56 
8.60 

•79 
•97 

10.22 
13-43 

70 
80 

67.14 
71.78 

7-39 
8.46 

14.78 
16.90 

:!£ 

2.71 
3-31 

.766 
.819 

6.10 
7-45 

.36 
.46 

10.84 
I3-24 

•13 

•27 

16.93 
20.69 

90 

9-53 

19.06 

•386 

3-95 

.864 

8.88 

•54 

15.80 

•44 

24.68 

100 

80.25 

10.56 

21.12 

.407 

4-63 

.916 

10.41 

•63 

18.52 

•54 

28.90 

"5 

89-72 

13.21 

26.42 

•455 

6-47 

.02 

14-55 

.82 

25-88 

.81 

40.40 

150 

98.28 

15-85 

3L70 

•499 

8.50 

.12 

19.12 

.00 

34.00 

3-" 

S3-12 

175 

106.  i 

18.50 

37.00 

•539 

10.70 

.21 

24.07 

.16 

42.80 

336 

66.86 

200 

"3-5 

21.14 

42.28 

.576 

13-1 

.29 

29-43 

•3° 

52.4 

3-50 

8i.75 

250 

127.1 

26.62 

52.84 

•644 

18.3 

•45 

.58 

73-2 

4.02 

114. 

300 

139.0 

3L70 

63.40 

>7°5 

24.0 

•59 

54-07 

.82 

96.0 

4.40 

150. 

350 

150.1 

37.08 

74.16 

.762 

30.3 

68.15 

3-05 

121.  2 

4.76 

189. 

400 

450 

160.5 
170.2 

42.27 

47.64 

84.54 
95.28 

.814 
.864 

37-o 
44-2 

^83 
•94 

83-25 
99-34 

3.26 

148.0 
176.8 

5-09 
5-40 

231. 
276. 

550 

179.4 
188.2 

52.84 
58.22 

105.7 
116.4 

.010 

•955 

59-7 

•05 

.10 

116.5 
I34-2 

3^64 
3-82 

206.8 
238.S 

5.60 

323- 
372.7 

600 

196.6 

63.41 

126.8 

•999 

68.0 

•23 

152.9 

272.0 

6.  '23 

475-o 

700     :2i2.3 

73-98 

148.0 

i.  06 

85-7 

•46 

,92.8 

4-36 

342.8 

6.79 

535-5 

800     226.9 

84.55 

l6g.I 

i  •  15 

104.7 

-58 

235-5 

4.60 

418.8 

7.19 

654.0 

goo      240.7 

95.I4 

190.3 

1.22 

124.9 

•75 

281.0 

4.88 

499.6 

7-63 

780.5 

1000 

253-8 

105.6 

211.  2 

1.29 

146.2 

.89 

329-0 

5-16 

584.8 

8.04 

914.0 

FLOW  OF  WATER   THROUGH  NOZZLES 


391 


TABLE    SHOWING    FLOW    OF    WATER    THROUGH    NOZZLES 

QUANTITY    AND    HORSE-POWER — (continued.) 


8 

II 

II 

Diameters  of  Nozzles. 

Head 

1 

.  0 

<S1 
O  en 

|| 

§•*• 

3  Inches, 

3.5  Inches. 

4  Inches. 

4.5  Inches. 

Feet. 

Feet. 

I) 

H.P. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

i 

8.025 

.308 

.424 

•  372 

.040 

•50 

.056 

.656 

.072 

.81 

.090 

i  .5 

9-83 

•474 

-632 

•444 

.076 

.61 

.105 

.800 

.136 

.00 

.171 

2 

"•35 

-633 

.844 

.520 

.116 

.70 

.160 

.928 

.208 

•17 

.260 

2-5 

12.68 

•792 

i.  06 

•58 

.164 

-79 

.224 

.02 

.288 

•30 

•370 

3 

13.90 

•951 

1.27 

-636 

.216 

.86 

•295 

.14 

-384 

•43 

4-85 

3-5 

15.01 

.110 

1.48 

.684 

.272 

•  94 

•37° 

.22 

.480 

•54 

.612 

4 

16.05 

.26 

1.68 

.742 

.332 

.02 

.452 

•30 

•  592 

.64 

.742 

4-5 

17.02 

.42 

1.90 

•776 

•396 

.06 

•  540 

•38 

.704 

•  7 

.815 

5 

17.95 

.58 

2.12 

.820 

•452 

.11 

.600 

.46 

.816 

.8 

.02 

6 

19.66 

.90 

2-54 

.896 

.612 

.22 

-833 

.60 

1.09 

.0 

•38 

7 

21.23 

.22 

2.96 

.968 

•772 

•32 

1.05 

•73 

1.38 

.  i 

•74 

7-5 

21.98 

•38 

3.16 

.00 

.856 

•36 

-78 

1.52 

.2 

.92 

10 

25.38 

3-18 

4-24 

.16 

1.32 

1.79 

.16 

2.34 

.6 

•97 

12.5 

28.37 

3  «9^ 

5.28 

•  30 

1  .  84 

•  7^ 

2.50 

•3° 

3-46 

.92 

4-14 

15 

4-77 

6.36 

.42 

2.42 

•93 

3-29 

•53 

4-32 

5-44 

17-5 

33-57 

5-55 

7-4°' 

•53 

3  *  *3 

.08 

4.20 

.72 

5-44 

3-44 

7-04 

20 
22.5 

35.89 
38-07 

6-33 
7.14 

8.44 
9-52 

•74 

3.72 

4-44 

•23 
-36 

5-07 
6.05 

-91 
3-09 

6.64 
7-92 

3-69 
3-91 

8-37 
9.99 

25 

40.13 

7-92 

10.56 

•83 

5.20 

•54 

7.08 

3-26 

9-24 

4.12 

ii  .70 

27-5 
30 

42.08 
43-95 

8.70 
9.06 

1  1.  60 
12.08 

.92 
•05 

6.00 
6.84 

.61 
•79 

8.17 

3-41 
3-65 

10.68 
12.  16 

4-32 
4.61 

T3-50 
!5-39 

32-5 

45-75 

10.02 

13.36 

.09 

7-72 

.84 

10.50 

3-71 

13-72 

4.70 

17-37 

35 

47-47 

II  .07 

14-76 

•17 

8.60 

•95 

11.71 

3-86 

iS-S2 

4.88 

19-35 

40 

50-75 

12.66 

16.88 

•32 

10.52 

14.33 

4.12 

18.72 

5-22 

23-67 

45 

14.25 

19.00 

.46 

12.56 

3-34 

17.10 

4-36 

22.40 

5-54 

28.25 

5° 

56*75 

15-84 

21  .12 

14.72 

3-S2 

20.03 

4.60 

26.24 

5-83 

32.12 

60 

62.10 

19.20 

25.36 

19.36 

3-86 

26.32 

5-04 

34-40 

6-39 

43-51? 

70 

67.14 

22.17 

29.56 

24.40 

4-i7 

33-17 

5-42 

43.36 

6.84 

54-90 

80 

71.78 

25-36 

33-86 

3.28 

20.80 

4.40 

40.55 

5.81 

52.96 

7.38 

67.05 

90 

76-13 

28.59 

38.12 

3-46 

35-52 

4-73 

48.37 

6.  16 

68.20 

7.78 

79.92 

IOO 

80.25 

31.68 

42.24 

3-66 

41-64 

4.98 

56.67 

6.52 

74.08 

8.23 

93-70 

125 

89.72 

39.63 

52.84 

4.08 

58.20 

5-57 

79.20 

7.28 

103.5 

9.18 

130.9 

98.28 

47  55 

63.40 

4.48 

76.48 

6.10 

104.10 

8.00 

136.0 

10.08 

172.1 

175 

2OO 

106.1 

I  TO      C 

55-50 

74-00 

4-84 

96.28 

6.60 

131.07 

8.04 

171.2 

10.89 
ii  .61 

216.6 
261.7 

250 
300 

350 

1  j  •  5 

127.1 
139.0 
150.1 

03  .42 
74.26 
95.10 

III.T 

105-7 
126.8 
148.3 

5-8o 
6.36 
6.84 

216.3 
272.6 

7.88 
8.63 
9-33 

223.92 
294-3 
371-2 

10.32 
11.28 

12.  2O 

292.8 
384-0 
484.8 

13.05 
14.31 
15-39 

u*  -  / 
370.2 

613.2 

400 

160.5 

126.8 

169.1 

7-32 

323-0 

9-97 

453-2 

13.04 

592.0 

16-47 

749-2 

450 

170.2 

142.9 

190.6 

7-76 

397-4 

10.58 

54i.o 

13.84 

707.2 

17.46 

894.2 

500 

179.4 

158.5 

211.4 

8.20 

406.0 

11.15 

627.0 

14.56 

827.2 

i8.45 

104.8 

550 

188.2 

174-7 

232.8 

8.40 

536.8 

11.69 

731.0 

15.28 

955-2 

18.90 

1208 

600 

196.6 

I9O.2 

253.6 

8.92 

611  .0 

12.21 

832.7 

15.96 

1080.0 

20.07 

1376 

700 

212.3 

221.9 

296.0 

9.84 

771.2 

13.31 

1051 

17.44 

1371.2 

22.14 

1735 

800 

226.9 

253-6 

338.2 

10.32 

942.0 

14.10 

1282 

I8.40 

1675.2 

23.22 

2119 

900 

1000 

240.7 
253-8 

285.4 
316.8 

380.6 
422.4 

11.00 

11.56 

1124 
1316 

14.9 
15.76 

1530 
1791 

19.52 
30.64 

1998.4 
2339.2 

24-75 
26.00 

2529 
2961 

392 


GOLD  TABLE  AND  HYDRAULICS 


TABLE    SHOWING    FLOW    OF    WATER   THROUGH    NOZZLES — 
QUANTITY    AND    HORSE-POWER (continued^) 


8 

LI 

•s'S 

|| 

Diameters  of  Nozzles. 

K 

^Cfa 

H-.fe 

Head 

^ 

c  ••* 

C  "** 

1 

*<! 

o  co 

5  Inches. 

5.5  Inches. 

6  Inches. 

7  Inches. 

Feet. 

Feet. 

$° 

H.P. 

1 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

Tubic 
Feet. 

H.P. 

i 

8.025 

.616 

8.8 

.02 

.116 

1.23 

.140 

1.49 

.100 

i-99 

.226 

1.5 

9-83 

.948 

1.26 

•25 

.212 

•  257 

1.78 

.304 

2-44 

.420 

2 

"•35 

1.27 

1.69 

•44 

.327 

1.74 

•  395 

2.08 

.464 

2.82 

.641 

2-5 

12.68 

1.58 

2.  II 

.61 

•457 

1-95 

•553 

2.32 

.656 

3-15 

.896 

3 

13.90 

1.90 

2-54 

.76 

.601 

2.13 

•727 

2.54 

.864 

3-45 

1.18 

3-5 

15.01 

2.22 

2.96 

.90 

•757 

2.31 

.916 

2.74 

1.09 

3.78 

1.48 

4 

16.05 

2-53 

3-37 

•°3 

•925 

2.46 

1.  12 

2.97 

i-33 

4.09 

i  .  81 

4-5 

17.02 

2.84 

3-79 

.16 

I.  10 

2.51 

1-33 

3-io 

1-58 

4.23 

2.16 

17.95 

3.  18 

4.24 

.27 

1.26 

2.75 

1-53 

3-28 

1.81 

4.40 

2.48 

6 

19.66 

3.81 

5-o8 

•49 

1.70 

3-02 

2.05 

3.58 

2-45 

4.88 

3-33. 

7 

21.23 

4-44 

5-92 

.69 

2.14 

3-26 

2-59 

3-87 

3-09 

5-28 

4.20 

7-5 

21.98 

4-74 

6.32 

•79 

2.38 

3-42 

2.87 

4.00 

3-42 

5-40 

4.66 

10 

25-38 

6.36 

8.48 

.22 

3-66 

3-89 

4.42 

4.64 

5-28 

6.30 

7.16 

12.5 

28.37 

7.92 

10.56 

•59 

5-" 

4-3 

6.18 

5-20 

7-36 

7-05 

IO.O2 

15 

31.08 

9-54 

12.72 

•94 

6.72 

4-76 

8.13 

5-68 

8.08 

7.72 

I3.I7 

17.5 

33-57 

II.  10 

14.80 

.26 

8.46 

5-15 

10.24 

6.12 

12.52 

8-34 

16.80 

20 

35-8o 

12.66 

16.88 

•55 

10.34 

5-50 

12.51 

6.56 

14.88 

8.92 

20.28 

22.5 

38-07 

14.28 

19.04 

•83 

12-34 

5-84 

6.96 

17.76 

9.46 

24.20 

25 

40.13 

15.84 

21.12 

5-09 

14.45 

6.16 

17-49 

7.32 

20.80 

10.15 

28.33 

27.5 

42.08 

17-40 

23.20, 

5-34 

16.67 

6.46 

20.18 

7.68 

24.00 

10.40 

32.08 

30 

43-95 

18.12 

24.16 

5.70 

19.00 

6.90 

22.99 

8.20 

27-36 

EX.  t8 

37-25 

32.5 

45-75 

20.04 

26.72 

5.80 

21.42 

7.02 

25.92 

8.36 

30.88 

11.37 

41.99 

35 

47-47 

22.14 

29.52 

6.02 

23-94 

7.28 

28.97 

8.68 

33-40 

Il.So 

46.84 

40 

50.75 

25.32 

33-76 

6.44 

29.25 

7-78 

83-39 

9.28 

42.08 

12.  6l 

57-33 

45 
50 

53.83 

29.50 
31.68 

38.00 
42.24 

6.82 
7.19 

34-90 
40.87 

8.26 
8.70 

42.23 
49-46 

9-84 
10.36 

50.24 
58.88 

13.38 
14.10 

68.40 
80.  ii 

60 

62.16 

38-04 

50.72 

7.88 

53-72 

9-54 

65.01 

11.36 

77-44 

15-44 

i°5-3 

70 
80 

67-14 
71.78 

44-34 
50-74 

59-12 
67.64 

8.51 

9.10 

67.72 
82.76 

10.30 

II.  01 

81.95 

100.  1 

12.24 
13-12 

97.60 
119.2 

16.09 
17.84 

132.7 
162.2 

90 

76-13 

57-i8 

76.24 

9.65 

98.72 

11.58 

119-5 

13.84 

142.1 

18.92 

193-5 

100 

80.25 

63-36 

84.48 

10.17 

115.6 

12.31 

139.9 

14.64 

166.6 

19-94 

226.7 

125 

89.72 

79.26 

95-68 

11.38 

161.6 

13-76 

195.0 

16.32 

232.8 

22.30 

316.8 

150 

98.28 

95.10 

126.8 

12.46 

212.5 

15.08 

257.0 

17.92 

305-9 

24.42 

416.4 

175 

106.1 

III.O 

148.0 

13.46 

267-5 

15-29 

313.7 

19.36 

385-1 

26.39 

524-3 

200 

250 

"3-5 
127.1 

126.8 
158-5 

169.1 
211.4 

14.34 
16.09 

327-0 
457-0 

17.51 
19-47 

395.7 

553-0 

20.64 
23.20 

470.8 
658.0 

28.20 
31-54 

640.9 
8-5-7 

300 

39-° 

190.2 

253.6 

17.62 

601  .0 

21-33 

726.9 

25-44 

865.2 

34-54 

"77 

350 

50.1 

222.5 

296.6 

19.04 

757-2 

22.04 

916.3 

27.36 

1090.4 

37-32 

1485 

400 

60.5 

253-6 

338.2 

20.35 

925.0 

24.62 

"79 

29.28 

1332 

29.89 

1813 

450 

70.2 

285.8 

381.1 

21.59 

1104 

26.  12 

1335 

31.04 

1590 

42.31 

2164 

500 

79-4 

317-1 

422.8 

22.75 

"93 

27-54 

1565 

32.80 

1864 

44.00 

2508 

550 
600 

88.2 
196.0 

349-2 
380.4 

465-6 
507.2 

23.86 
24.93 

i49i 
1699 

28.88 
30.l6 

2056 

33-60 
35-08 

2147 
2446 

46.78 
48.86 

2923 

333  1 

700 
800 

212.3 
226.9 

444.0 
507.3 

592.0 
676.4 

27.18 

28.77 

2142 
2616 

32.88 
34-92 

2591 
3166 

39-36 
41.28 

3085 
3768 

53-26 
56.40 

4203 
5129 

900 

240.7 

570-9 

761.2 

30.52 

3122 

36.94 

3778 

44.00 

4496 

59-83 

6120 

IOOO 

253-8 

633-6 

844-8 

32.17 

3656 

38.93 

4424 

46.24 

5264 

63.06 

7166 

FLOW  OF  WATER  THROUGH  NOZZLES 


393 


TABLE    SHOWING    FLOW    OF    WATER    THROUGH    NOZZLES — 
QUANTITY    AND    HORSE-POWER. 


1 

IS 

|j 

Diameters  of  Nozzles. 

jjfc 

c  fe 

£ 

G 

*"*  CJ 

Head 

ex 

1 

•-•.y 

C*  3 
$ 

13 

§0 

8  Inches. 

9  Inches. 

10  Inches. 

12  Inches. 

Feet. 

Feet. 

§> 

H.P. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

i 

8.025 

i.  06 

2.12 

2.62 

.288 

3-35 

.360 

4.07 

.46 

5-96 

.904 

1.5 

9-83 

1.58 

3-l6 

3-20 

•544 

3-99 

.684 

4-99 

•85 

7.12 

1.68 

2 

"•35 

2.  II 

4.22 

3-7* 

1  132 

4.68 

1.04 

5.76 

!•! 

8.32 

2.56 

2-5 

12.68 

2.64 

5.28 

4-08 

5-22 

1.48 

6-44 

1.83 

9.28 

3.58 

3 

13.90 

3-17 

6-34 

4-56 

1-54 

5-72 

1.94 

7-°5 

2.40 

10.  16 

4.72 

3-5 

15-01 

3-70 

7.40 

4-88 

1.92 

6.16 

2-45 

7.62 

3.03 

10.96 

5-92 

4 

16.05 

4.21 

8.42 

5.20 

2-37 

6.58 

2.99 

8.14 

3.70 

n.88 

7  24 

4-5 

17.02 

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9.48 

5-52 

2.81 

6.98 

3-26 

8.64 

4.42 

12.40 

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5.28 

10.6 

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3-26 

7.38 

4.07 

9.10 

5.05 

9.92 

6 

19.66 

6-34 

12.7 

6.40 

4.36 

8.06 

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6.80 

14.32 

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7 

21.23 

7-39 

14.8 

6.92 

5-52 

8.71 

6-95 

10.77 

8.57 

15.48 

16.80 

7-5 

21.98 

7.92 

15-8 

7.12 

6.08 

9.00 

7.70 

11.14 

9.50 

16.00 

18.64 

10 

25.38 

10.6 

21.2 

8.64 

9.36 

10.41 

it.  88 

12.87 

14.63 

i8.n6 

28.64 

12.5 

28.37 

13.2 

26.4 

9.20 

13  84 

1.70 

16.56 

14-39 

20.44 

20.80 

40.08 

15 
17-5 

31-08 
33-57 

3:! 

31-8 
37-o 

10.12 

10.88 

17.28 

21  .76 

2.78 
3-77 

21.78 
28.17 

J5.76 

26.87 

33-86 

22'.  72 
24.48 

52.68 
67.20 

20 

35.89 

21.  1 

42.2 

11.64 

26.56 

4.76 

33.48 

18.20 

41-37 

26.24 

81.12 

22.5 

38.07 

23.8 

47-6 

12.36 

31  .68 

5-66 

39.96 

I9>31 

49-37 

27.84 

96.80 

25 

40.13 

26.4 

52.8 

13.04 

36.96 

6-47 

46.80 

20.35 

57-82 

29.28 

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42.08 

29.0 

58.0 

13-64 

42.72 

7.28 

54-00 

21-34 

66.70 

30.72 

130.7 

3° 

43.95 

30.2 

60.4 

14.60 

48.64 

8-45 

61.56 

22.81 

76.01 

32.80 

149.0 

32.5 
35 

45.75 
47.47 

33-4 
36.9 

66.8 
73-8 

14.84 
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54.88 
61.28 

8.81 
9-53 

69.48 
77.40 

23.20 
24.08 

85.70 
95-78 

33-44 
34-72 

168.9 
187.4 

40 

50.75 

42.2 

84-4 

16.48 

74-88 

20.88 

94-68 

25-74 

117.0 

37-12 

229.3 

45 

53.83 

47-5 

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17.44 

89.60 

22.14 

113.0 

27.3° 

139-6 

39.36 

273.6 

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56.75 

52.8 

105.6 

18.40 

105.0 

23-31 

128.5 

28.78 

'63.5 

41.44 

320.4 

60 

62.16 

63-4 

126.8 

20.16 

137.6 

25.56 

174.2 

31.53 

214.9 

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421.2 

70 

67.14 

73.9 

147.8 

21.68 

173-4 

27.54 

219.6 

34.06 

270.9 

48.96 

530.8 

80 

71.78 

84.6 

169.0 

23.36 

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29.52 

268.2 

36.41 

331.0 

52.48 

648.8 

90 

76.13 

95-3 

190.6 

24.64 

252.8 

3'9-7 

38.61 

394-9 

55.36 

774.0 

100 

80.25 

106.6 

211.  2 

26.08 

296.3 

32.94 

374-8 

40.70 

462.5 

58.56 

906.8 

125 

89.72 

132.1 

264.2 

29.12 

414.0 

36.72 

523.8 

45-Si 

646.5 

65.28 

1267 

150 

98.28 
106.1 

158.5 
185.0 

3*7.0 
370.0 

32.00 
34-56 

554-o 
684.8 

40.32 
43  •  56 

688.3 
866.5 

49.85 
53.85 

849.8 
1070 

71.68 
77-44 

1666 
2097 

200 

211.4 

422.8 

36.80 

878.4 

46.44 

1059 

57.56 

1308 

82.56 

2564 

250 

127.1 

264.2 

528.4 

41.28 

1171 

52.20 

1481 

64.36 

1828 

92.80 

3583 

300 

139.0 

317   0 

634.0 

45.12 

1536 

57-24 

"947 

70.50 

2403 

101.76 

4708 

350 

150.1 

370.8 

741.6 

48.80 

1949 

61.56 

2453 

76.15 

3029 

109. 

594° 

400 

160.5 

422.7 

845.4 

52.16 

2368 

65.88 

2997 

81.41 

3700 

117. 

7252 

45° 

170.2 

476.4 

952.8 

55.36 

2829 

69.84 

3577 

86.35 

4415 

124. 

8656 

500 
550 

x79-4 
188.2 

528.4 
582.2 

1057 
1164 

58.24 
61.12 

3409 
3821 

73.80 
75.60 

4194 
4831 

91.02 
95.46 

5966 

'34- 

1003* 
11692 

600 
700 
800 

196.6 
212.3 
226.9 

634.1 
739-8 
845-5 

1268 
1480 
l6gi 

63-84 
69.76 
73.60 

5485 
6701 

80.28 
88.56 
92.88 

5504 
6191 
8478 

99.71 
108.7 
115-1 

6798 
8567 
10468 

142.7 
157-4 
165.1 

13324 
16812 
20516 

900 
1000 

240.7 
253-8 

951-4 
1056 

1903 
2112 

78.08 
82.56 

7994 
9357 

99.00 
104.0 

10116 
11844 

122.5 
128.7 

12489 
14624 

176.0 
185.0 

24480 
28664 

394  GOLD  TABLE  AND  HYDRAULICS 

EXPLANATION  OF  PIPE  TABLES. 

The  tables  for  sheet-iron  pipe  are  arranged  as  follows: 

COLUMN  No.  i  gives  the  diameter  of  the  pipe  in 
inches, 

COLUMN  No.  2  is  the  area  in  square  inches  corre- 
sponding to  the  diameter. 

COLUMN  No.  3  is  the  thickness  of  the  iron  or  steel  in 
decimal  parts  of  an  inch. 

COLUMN  No.  4  is  the  thickness  of  the  iron  or  steel  by 
the  Birmingham  wire  gauge. 

COLUMN  No.  5  is  the  working  pressure  the  pipe  will 
be  subjected  to  in  pounds  per  square  inch,  allowing 
10,000  pounds  tensile  strain  per  sectional  inch  of  iron, 
deducting  25  per  cent  for  riveted  joints. 

For  steel  pipes  use  14,000  pounds  tensile  strain  per 
sectional  inch;  deduct  25  per  cent  for  riveted  joints. 
Hence,  working  pressure  for  steel  pipe  may  be  taken 
40  per  cent  higher  than  given  in  table. 

COLUMN  No.  6  is  the  number  of  cubic  feet  of  water 
that  will  flow  through  the  pipe  in  one  minute,  when 
the  velocity  of  the  water  is  10  feet  per  second. 

COLUMN  No.  7  is  an  approximation  of  the  weight 
of  a  lineal  foot  of  pipe,  including  rivets. 

The  cost  of  pipe  varies  with  the  iron  market,  and 
the  quantity  ordered  of  one  diameter  and  thickness  — 
small  lots  costing  sometimes  50  per  cent  more  than 
large  orders. 

The  charge  is  extra  for  dipping  pipes  in  asphaltum  — 
coating  them  inside  and  outside  —  and  the  cost  of  dip- 
ping small  pipes  is  about  one  cent  for  each  inch  in 
diameter  and  one  foot  in  length. 

Coating  with  asphaltum  adds  about  one  third  of  a 
pound  per  square  foot  to  the  pipe. 


P.IPE  TABLES 


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i 

94 

5232 

132 

40 

1256 

•259 

3 

97 

5232 

138 

40 

1256 

•3125 

A 

117 

5232 

169 

40 

1256 

•375 

I 

141 

5232 

205 

42 

1385 

•  134 

10 

48 

5769 

74* 

42 

1385 

.165 

8 

59 

5769 

91 

42 

1385 

.180 

7 

64 

5769 

102 

42 

1385 

.203 

6 

72 

5769 

114 

42 

1385 

.238 

4 

85 

5769 

133 

42 

1385 

.250 

i 

89 

5769 

137 

42 

1385 

•  259 

3 

92 

5769 

145 

42 

1385 

.3125 

T6* 

in 

5769 

177 

42 

1385 

•  375 

1 

134 

5769 

216 

44 

1520 

•  134 

10 

45 

6332 

78 

44 

1520 

.165 

8 

56 

6332 

95 

44 

1520 

.180 

7 

61 

6332 

1  06 

44 

1520 

.203 

6 

-   69 

6332 

119 

44 

1520 

.238 

4 

81 

6332 

139 

44 

1520 

.250 

^ 

85 

6332 

145 

44 

1520 

.259 

3 

88 

6332 

151 

44 

1520 

.3125 

T7T 

1  06 

6332 

185 

44 

1520 

•375 

J. 

128 

6332 

225 

48 

1809 

•  134 

10 

42 

7536 

85 

48 

1809 

.165 

8 

51 

7536 

103 

48 

1809 

.180 

7 

56 

7536 

116 

48 

1809 

.203 

6 

63 

7536 

130 

48 

1809 

•  238 

4 

75 

7536 

151 

48 

1809 

.250 

i 

78 

7536 

158 

48 

1809 

•  259 

3 

81 

7536 

164 

48 

1809 

A 

98 

7536 

210 

48 

1809 

•  375 

1 

117 

7536 

245 

400  GOLD  TABLE  AND   HYDRAULICS 

FLOW  OF  WATER  THROUGH  RECTANGULAR   ORIFICES 
IN  THIN  VERTICAL  PARTITIONS. 

Question:  The  head  being  10  feet,  and  the  gate- 
opening  being  6  inches  high  and  i  foot  wide,  what  will 
be  the  discharge  in  miner's  inches  ? 

Answer:  In  this  table,  opposite  lofeet  in  first  column, 
find  in  column  headed  6  Inches  High,  i  Foot  Wide, 
7.62  cubic  feet.  Multiply  this  number  by  50,  the  number 
of  miner's  inches  in  i  cubic  foot,  and  there  results  762  X 
50  =  381.00  miner's  inches. 

Question:  The  head  being  25  feet  and  the  opening 
iT8u-  inches  high,  i  foot  wide,  how  many  pounds  will 
be  discharged  per  second  ? 

Answer:  In  this  table,  opposite  25  feet  in  first  column, 
find  in  column  headed  1.5  Inches  High,  i  Foot  Wide, 
3.05  cubic  feet.  Multiply  this  number  by  62.5,  the  num- 
ber of  pounds  in  a  cubic  foot.  3.05  X  62.5  =  190.625 
pounds. 

Question:  The  head  being  7  feet  and  the  opening 
i  inch  high,  i  foot  wide,  what  will  be  the  discharge  in 
cubic  feet  ? 

Answer:  In  this  table,  opposite  7  feet  in  first  column, 
find  in  column  headed  3  Inches  High,  i  Foot  Wide, 
3.24  cubic  feet.  The  given  height  i  inch  is  one-third  of 
3  inches,  the  height  of  the  opening;  hence,  without  sen- 
sible error,  we  may  take  one-third  the  flow  due  3  inches 
for  that  opening.  3.24  •*-  3  =  1.08. 


FLOW  OF  WATER 


401 


TABLE    SHOWING     FLOW    OF    WATER    THROUGH    REC- 
TANGULAR ORIFICES  IN  THIN  VERTICAL  PARTITIONS. 


u  8 

Breadth  and  Height  of  Orifice. 

8 

>>  o 

i  ft.  High, 
i  ft.  Wide. 

9  in.  High, 
i  ft.  Wide. 

6  in.  High, 
i  ft.  Wide. 

3  in.  High, 
i  ft.  Wide. 

1.5  in.  High, 
i  ft.  Wide. 

2 

•5 

Feet. 

Feet. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

H.P. 

Cubic 
Feet. 

HP. 

Cubic 
Feet. 

H.P. 

.028 

O.  2 

3-  5 

o  .  69 

.022 

4 

«3 

4.4 

jjk 

.80 

•  40 

.018 

.4 

5-°7 

2    c*7 

.146 

•  5U 

.  74 

099 

.89 

.O5I 

•  5 
.6 

6^22 

3-72 

•  253 

2.83 

.193 

•  91 

.130 

.066 

•  49 

•033 

.7 

6.72 

4.02 

.317 

3.06 

.249 

.07 

.165 

'.06 

.082 

•53 

.041 

.8 

6.38 

4-3i 

•  392 

3-27 

.297 

.21 

.201 

•  14 

,104 

•57 

.052 

•  9 

7.62 

4-57 

.467 

3.48 

.356 

•  35 

.240 

.20 

.122 

.60 

.061 

I.O 

8.025 

4-87 

•  554 

3.67 

.417 

-48 

.281 

.26 

.144 

.63 

.072 

1.25 

8-99 

5-29 

•751 

4.02 

•  571 

.385 

•39 

.197 

.69 

.008 

1.50 

9.83 

5-92 

.01 

4-50 

.767 

3-03 

•517 

•  55 

.259 

•  77 

.129 

1.75 

10-59 

6.  .40 

.27 

4.86 

.967 

3-27 

.650 

.67 

.326 

•83 

.163 

2.00 

11-35 

6.85 

•  56 

5-20 

.18 

3-50 

•  795 

•  79 

.398 

.89 

.199 

2.25 

12.  OO 

7.27 

.86 

5-51 

41 

3-71 

•949 

-89 

•  475 

•95 

•  237 

2.50 

12.68 

7.67 

.18 

5-8i 

.65 

3-91 

I.  ii 

-99 

.565 

I.  00 

.283 

2-75 

3-oo 

13-32 
13.90 

8.05 
8.41 

•  53 

6.09 

.86 

4.10 
4.27 

1.28 
1.46 

:3 

•  654 

•  743 

1.04 
1.09 

•  327 
•  371 

3-  SO 

15.01 

9.08 

3^6i 

6^se 

•  73 

4.61 

1-83 

•  35 

-935 

1.17 

.467 

4.00 

16.65 

9-97 

4-54 

7-32 

3-33 

4.92 

2.24 

-50 

I-I4 

1-25 

•  568 

4-50 

17.02 

10.29 

5-26 

7-75 

3.96 

5-21 

2.66 

1.36 

1.32 

.678 

5.00 

17-95 

10.84 

6.16 

8.16 

4-64 

5-49 

3-12 

•  7^ 

1.58 

1-39 

.781 

6 

19.66 

11.84 

8.08 

8.91 

6.08 

5-98 

4.08 

3-03 

2.07 

LSI 

1.03 

7 

21.23 

12.76 

10.  14 

9.61 

7-64 

6-43 

5.12 

3-  24 

2.58 

1.62 

1.29 

8 

22.71 

13-64 

12.40 

10.25 

9-32 

6.84 

6.22 

3-45 

3-14 

1.71 

1.50 

9 

24.70 

14.47 

14.80 

10.86 

ii.  ii 

7-25 

7.42 

3-64 

3-72 

1.83 

1.82 

10 

25-38 

15-25 

17-34 

n-44 

13.00 

7.62 

8.66 

3-83 

4-34 

1.92 

2.18 

IS 

31.08 

18.68 

31-85 

14.01 

23.88 

9-34 

15-93 

4-69 

8.00 

2.36 

4.02 

20 

35-89 

21.50 

49-05 

16.18 

36.78 

10.8 

24-55 

5.42 

12.  29 

2.72 

6.15 

25 

40.13 

24.12 

68.52 

18.10 

51-42 

12.08 

34-32 

6.06 

17.22 

3-05 

8.67 

30 

43-95 

26.43 

00.  IO 

19.84 

67.64 

13-47 

4^.92 

6.64 

22.64 

3-35 

11.42 

35 

47-47 

28.55 

113.6 

21.44 

85.27 

14-31 

<;6.o6 

7.18 

28.56 

3-62 

14-40 

40 

50.75 

30-53 

138.8 

22.94 

104.3 

15.32 

69.64 

7.68 

34-91 

3-79 

17-23 

45 
50 

53.83 
56.75 

32-39 
34-15 

165.6 

194.0 

24-35 
25.68 

124.5 
145.8 

16.26 
17.16 

83.14 
97-50 

8.16 
8.61 

41-73 
48.92 

4.12 
4-35 

21.02 
24.72 

402 


GOLD   TABLE  AND   HYDRAULICS 


VOLUMES    OF    WATER   REQUIRED   FOR  EFFECTIVE  USE 
IN    OPERATING   HYDRAULIC   GIANTS. 


2  -Inch 

2^-Inch 

3-Inch 

4-Inch 

5  -Inch 

Head. 

Nozzle. 

Nozzle. 

Nozzle. 

Nozzle. 

Nozzle. 

Feet. 

Miner's 

Miner's 

Miner's 

Miner's 

Miner's 

Inches. 

Inches. 

Inches. 

Inches. 

Inches. 

100 

80 

125 

185 

325 

500 

15° 

IOO 

155 

225 

400 

625 

200 

H5 

180 

260 

460 

7i5 

250 

130 

200 

290 

5iS 

800 

300 

140 

220    . 

320 

565 

880 

35° 

ISO 

24O 

345 

610 

950 

400 

160 

255 

365 

650 

1000 

The  area  of  circles  in  square  feet  may  be  obtained 
from  the  following  table,  —  which  is  also  the  number 
of  cubic  feet  in  i  foot  length  of  the  pipe.  (Trautwine.) 


Diameter. 
Inches. 

Area. 
Sq.  Feet. 

Diameter. 
Inches. 

Area. 
Sq.  Feet. 

Diameter 
Inches. 

Area. 
Sq.  Feet. 

I 

.0003 

3i 

.0576 

gj 

.2131 

1 

.0014 

3i 

!o668 

fil 

.2304 

J 

.0031 

3l 

.0767 

6f 

.2485 

r 

•°°55 

4 

.0873 

7 

.2673 

if 

.0085 

4i 

.0985 

71 

.2867 

{1 

.0123 

4i 

.  1104 

7i 

.3068 

if 

.0167 

4l 

.1231 

7t 

.3276 

2 

.0218 

5 

•1363 

8 

•3491 

2f 

.0276 

Si 

8J 

.3712 

2I 

.0341 

5f 

.1650 

8} 

•3941 

2f 

.0412 

Si 

•1803 

8| 

.4176 

3 

.0491 

6 

.1964 

9 

.4418 

To  Find  the  Square  Root  of  a  Number:  Separate  the 
given  number  into  periods  of  two  each,  beginning  at 
unit's  place,  thus:  18,  66,  24;  or  if  the  number  be  a  deci- 


FLOW  OF  WATER  403 

mal  fraction,  work  both  right  and  left  from  unit's  place, 
thus:  i,  96,  13,  69. 

Find  the  greatest  number  whose  square  will  go  into 
the  first  period,  and  subtract  this  square;  to  the  remain- 
der annex  the  next  period.  Divide  this  new  dividend 
by  twice  the  square  root  already  found,  multiplied  by  10 
for  a  trial  divisor.  The  quotient  thus  found  add  to  the 
trial  divisor;  it  is  the  next  figure  of  the  root.  Multiply 
this  divisor  by  the  last  root  figure  and  subtract  as  in  the 
first  instance,  etc. 
Example.  —  Find  the  square  root  of  186624. 

18,  66,  24(432 
4X4=        16 

4X2=    8  X  10  =    80  +  3  =  83)  266 
83  X  3  =          249 

80  +  3  X  2  =  86  X  10  =  860  +  2  =  862    1724 

862  X  2  =  1724 

Example.  —  Find  the  square  root^of  58.140625. 

58.  14  06  25    \j.fa$Ans. 

49 
7X2  =  14X10  =  140+6=146      914 

146  X  6  =  876 

140  .3806 

12  =  6X2 

152  X  10  =  1520  +  2  =  1522 

1522  X  2  =  3044 

1520  76225 

4=2X2 

1524  X  10  =  15240  +  5  =  15245 

15245  X  5  =  76225 
Example.  —  Find  the  square  root  of  196.1369. 

Answer.     14.0048+. 


404 


"GOLD  TABLE  AND   HYDRAULICS 


TABLE  OF  SAFE  HEAD  FOR  RIVETED  HYDRAULIC  PIPE. 

SHOWING    PRICE   AND  WEIGHT    WITH    SAFE    HEAD    FOR    VARIOUS 

SIZES  OF  DOUBLE-RIVETED  PIPE. 


Cub.  Ft. 

Diameter 
of 
Pipe  in 
Inches. 

Area  of 
Pipe 
in 
Inches. 

Thickness 
of  Iron 
by  Wire 
Gauge. 

Head  in 
Feet  the 
Pipe  will 
safely 
stand. 

of  Water 
Pipe  will 
convey 
per  min. 
at  Vel. 

Weight 

Lineal 
Foot 
in  Lbs. 

Price  per 
Foot. 

3  ft.  Per 

second. 

3 

7 

IS 

4OO 

9 

2 

$0.20 

4 

12 

18 

350 

16 

H 

•25 

4 

12 

16 

525 

16 

3 

•35 

5 
5 

20 
20 

18 
16 

325 
500 

25 
25 

ll 

•35 
•45 

5 

20 

14 

675 

25 

5 

•50 

6 

28 

18 

296 

36 

4J 

.44 

6 

28 

16 

487 

36 

5- 

•50 

6 

28 

14 

743 

36 

7^ 

.56 

7 

38 

18 

254 

50 

5 

•  50 

7 

38 

16 

419 

50 

6; 

.56 

7 

38 

14 

640 

50 

8, 

.63 

8 

50 

16 

367 

63 

7- 

•65 

8 

50 

14 

560 

63 

9i 

•75 

8 

50 

12 

854 

63 

13 

•94 

9 

63 

16 

327 

80 

8 

.69 

9 

63 

14 

499 

80 

10 

.88 

9 

63 

12 

761 

80 

M 

1.06 

10 

78 

16 

295 

100 

9: 

.72 

10 

78 

14 

450 

100 

II: 

.82 

10 

78 

12 

687 

100 

15- 

1.  00 

10 

78 

II 

754 

IOO 

*7i 

1.25 

10 

78 

10 

900 

100 

J93 

1.50 

ii 

95 

16 

269 

1  20 

9l 

•  75 

ii 

95 

14 

412 

120 

13 

•94 

ii 
ii 

95 
95 

12 
II 

626 

687 

120 
120 

iTt 

i8f 

1-25 
1.44 

ii 

95 

10 

820 

120 

21 

1.62 

12 

H3 

16 

246 

142 

Hi 

.82 

12 

H3 

14 

377 

142 

14 

1.  00 

12 

H3 

12 

574 

142 

lS4 

1.38 

12 

113 

II 

630 

142 

I9f 

1.50 

12 

H3 

10 

753 

142 

22f 

1.69 

I 

SAFE  HEAD  FOR  RIVETED  HYDRAULIC  PIPE    405 


SAFE  HEAD  FOR  RIVETED  HYDRAULIC  PIPE.—  (Continued.) 


Diameter 
oi 
Pipe  in 
.  Inches. 

Area  of 
Pipe 
in 
Inches, 

Thickness 
of  Iron 
by  Wire 
Gauge. 

Head  in 
Feet  the 
Pipe  will 
safely 
stand. 

Cub.  Ft. 
of  Water 
Pipe  will 
convey 
per  min. 
at  Vel. 
3  ft.  per 
second. 

Weight 

Lineal 
Foot 
in  Lbs. 

Price  per 
Foot. 

13 

132 

16 

228 

170 

12 

$0.90 

13 

132 

14 

348 

170 

15 

1.  12 

13 

132 

12 

530 

170 

20 

1-50 

13 

132 

II 

583 

170 

22 

1.65 

13 

I32 

10 

696 

170 

24* 

1.  80 

14 

rs3 

16 

211 

200 

13 

.98 

14 

153 

14 

324 

2OO 

16 

I.I7 

14 

153 

12 

494 

2OO 

2I]£ 

1.57 

14 

153 

II 

543 

200 

23* 

1.72 

14 

153 

10 

648 

200 

26 

1-95 

15 

176 

16 

197 

225 

13! 

.96 

15 

176 

14 

302 

225 

17 

1.28 

15 

176 

12 

460 

225 

23 

1-75 

15 

176 

II 

507 

225 

24* 

1-95 

15 

176 

10 

606 

225 

28 

2.10 

16 

201 

16 

185 

255 

'4i 

1.05 

16 

201 

14 

283 

255 

J7; 

1.20 

16 

201 

12 

432 

255 

24; 

1.70 

16 

2O  I 

II 

474 

255 

26i 

1.85 

16 

201 

10 

567 

255 

291 

2.00 

18 

254 

16 

165 

'  320 

i6j 

1.20 

18 

254 

14 

252 

320 

2Oi 

I.4O 

18 

254 

12 

385 

320 

27; 

I.90 

18 

254 

II 

424 

320 

30 

2.IO 

18 

254 

IO 

505 

320 

34 

2.40 

20 

3M 

16 

148  ' 

400 

18 

1.26 

20 

14 

227 

400 

22^ 

1-54 

20 

314 

12 

346 

400 

30 

2.IO 

20 

314 

II 

380 

400 

32i 

2.25 

20 

314 

10 

456 

400 

s4 

2.5O 

22 

380 

16 

135 

480 

20 

I.4O 

22 
22 
22 

380 
380 
380 

14 

12 

II 

206 
316 

347 

480 
480 
480 

a 

351 

1.70 
2.25 
2-45 

22 

380 

IO 

415 

480 

40 

2.80 

24 

24 

452 
452 

14 

12 

188 
290 

570 
570 

•7f 

35* 

1.80 

2.35 

24 

452 

II 

318 

570 

39 

2.70 

24 

452 

10 

379 

570 

2.95 

24 

452 

8 

466 

570 

53 

3-50 

406 


GOLD  TABLE  AND  HYDRAULICS 


SAFE  HEAD  FOR  RIVETED  HYDRAULIC  PIPE.— (Continued.} 


Diameter 
of 
Pipe  in 
Inches. 

Area  of 
Pipe 
in 
Inches. 

Thickness 
of  Iron 
by  Wire 
Gauge. 

Head  in 
Feet  the 
Pipe  will 
safely 
stand. 

Cub.  Ft. 
of  Water 
Pipe  will 
convey 
per  min: 
at  Vel. 
3  ft.  per 
second. 

Weight 
per 
Lineal 
Foot 
in  Lbs. 

Price  per 
Foot.  , 

26 

530 

14 

175 

670 

29i 

f  2.OO 

26 

530 

12 

267 

670 

38i 

2-59 

26 

530 

II 

2Q4 

670 

42 

2.87 

26 

530 

10 

352 

670 

47 

3.10 

26 

530 

8 

432 

670 

57i 

3.85 

28 

615 

14 

102 

775 

3'i 

2.12 

28 

615 

12 

247 

775 

4l| 

2.75 

28 

615 

II 

273 

775 

45 

3.00 

28 
28 

6'5 
615 

IO 

8 

327 
400 

775 
775 

£1 

3-20 

4-15 

30 

706 

12 

231 

890 

44 

2.90 

30 

706 

II 

254 

8qO 

48 

3-15 

30 

706 

10 

304 

890 

54 

3-50 

30 

706 

8 

375 

890 

65 

4.30 

30 

706 

7 

425 

890 

74 

4.75 

36 

1017 

ii 

141 

1300 

58 

3.80 

36 

1017 

10 

155 

1300 

67 

4-30 

36 

1017 

8 

192 

1300 

78 

5.10 

36 

1017 

7 

210 

1300 

88 

5.75 

40 

1256 

IO 

141 

1600 

7i 

4.75 

40 

1256 

8 

174 

1600 

86 

5.60 

40 

1256 

7 

I89 

1600 

97 

6.40 

40 

1256 

6 

213 

1600 

108 

7-35 

40 

1256 

4 

25O 

1600 

126 

8.50 

42 

1385 

10 

135 

1760 

74^ 

5-05 

42 

1385 

8 

165 

1760 

9i 

6.  20 

42 

1385 

7 

1  80 

1760 

102 

7.00 

42 

1385 

6 

210 

1760 

114 

7.80 

42 

1385 

4 

24O 

1760 

133 

9.00 

42 

1385 

* 

27O 

1760 

137 

9-50 

42 

1385 

3 

300 

1760 

145 

10.00 

42 

1385 

T6* 

321 

1760 

177 

12.00 

42 

1385 

f 

363 

1760 

216 

15.00 

NOTE. — Where  formed  and  punched  including  rivets,  for  mule  packing  or  to 
facilitate  transportation  by  other  means,  30  per  cent  may  be  deducted  from  prices 
above  given.  This  list  is  based  upon  pipe  coated  inside  and  out  with  asphaltum, 
and  is  given  for  the  purpose  of  enabling  parties  to  make  an  approximate  estimate 
of  the  cost.  Net  prices  will  be  quoted  on  application. 


TABLE  OF  VELOCITIES 
TABLE   OF   VELOCITIES. 


407 


•a 

'•a 

1 

a 
,o 

fj 

Discharge  per  Second  through  Nozzles. 

c 

'i  <- 

>  *« 

1 

15 

it 

.'  / 

j 

rC 

1 

Z£ 

i 

10 

25.4 

26.32 

11.18 

44-30 

99-78 

177.4 

277.0 

399.1 

682.2 

709.4 

2O 

35  9 

28.72 

•15-79 

62.61 

141.0 

250.8 

39r-4 

564.1 

767.7 

1026 

30 

43-9 

35-12 

19.32 

76.56 

173-9 

306.6 

478.7 

689.7 

938.8 

1226 

40 

5°-7 

40.56 

22.31 

89.24 

199-3 

354-1 

552.8 

796.7 

1085 

1416 

5° 

56.7 

45-36 

24-95 

98.88 

222.7 

396-0 

618.4 

890.9 

1213 

1584 

60 

62.! 

49.68 

27.33 

108.30 

243-9 

433-7 

677.1 

975-7 

1328 

70 

67.1 

53.68 

29-52 

117.01 

263-5 

468.6 

731-7 

1053 

1435 

1874 

80 

71.8 

57-44 

31.66 

125.24 

282.0 

SOLS 

783.9 

1129 

1535 

2005 

90 

76.1 

60.88 

33-49 

132.87 

298.9 

531-4 

829.8 

1196 

1627 

2126 

100 

80.3 

64.24 

35-33 

140.32 

308.9 

560.8 

874-6 

1262 

1717 

2243 

no 

84.2 

67-36 

37.05 

146.82 

^30.8 

588.0 

918.1 

X323 

1801 

2352 

120 

87.96 

70.36 

38.70 

153-48 

345-5 

614.3 

959-0 

1382 

1881 

2456 

130 

91-54 

73.23 

40.28 

I59-92 

359-5 

630  •  3 

998.1 

1439 

1958 

2556 

140 

94.99 

75-99 

41.80 

J65-73 

37|.i 

663,4 

1036 

M93 

2031 

2653 

*5O 

98.3 

78.64 

43.26 

I7I«54 

386.1 

686  «5 

1072 

1545 

2IO2 

2745 

1  60 

101.49 

81.19 

177.26 

398.5 

708.8 

1107 

1595 

2170 

2834 

170 

104.56 

83.62 

45.99 

182.36 

410.5 

718.4 

1140 

1643 

2236 

2919 

180 

107.76 

86.20 

47-41 

188.16 

423.2 

752.5 

1176 

1693 

2305 

3009 

190 

110.65 

88.52 

48.69 

192.92 

434-7 

772.8 

1207 

^739 

2366 

3091 

200 

"3-54 

90.83 

49-94 

198.16 

446.0 

793-° 

1238 

1784 

2428 

210 
220 

116.35 
119.08 

93.08 
95.26 

51-20 
52.49 

203  .  80 
207  .  82 

457-0 
467-8 

812.6 
831-7 

"59 
1299 

1828 
1872 

2488 
2547 

3250 
3326 

230 

121.73 

97.38 

53.56 

212.33 

478.1 

850.1 

1323 

19*3 

2604 

240 

124 

99-2 

54-56 

216.2 

487.0 

866.0 

1352 

1948 

2652 

3463 

250 

126 

100.8 

55-44 

219.8 

495-0 

888.0 

1374 

1980 

2694 

260 

129 

103.2 

56-76 

225.0 

560.7 

900.9 

1407 

2027 

2759 

3603 

2/0 

104.8 

57.64 

228.5 

514.6 

914.9 

1428 

2059 

2801 

3649 

280 

J34 

107.2 

58.96 

233-7 

526.3 

935-9 

1461 

2105 

2865 

3742 

290 

136 

108.8 

59.84 

237.7 

534-1 

949-9 

1483 

2127 

2909 

3798 

300 
3IO 
320 

139 
141 
143 

in.  a 

112.8 

114.4 

60.32 
61.64 
62.92 

239.1 

240-3 
249.4 

538.8 
541-2 
561.7 

957-5 
962.3 
998.8 

1503 

2154 
2165 
2246 

2932 
2947 
3058 

3819 
3835 
3993 

33° 
34C 

MS 

148 

IIO.O 

1,8.4 

63.80 
64.61 

252-9 
256.1 

569-6 
576.8 

1012 
1025 

Jfp 

1601 

2278 
2307 

3IOO 

3*4° 

4050 
4101 

35° 

120.0 

66.00 

261.6 

589-2 

1047 

1635 

2357 

3207 

4189 

360 

152 

121.  6 

66.88 

262.5 

597-1 

1062 

1658 

2388 

3245 

4245 

370 
380 

156 

123.2 
124.8 

67.76 
68.64 

265.1 
272.1 

604.9 
612.8 

1075 
1090 

1679 
1701 

2419 
2449 

3293 
3336 

4301 
4358 

390 

158 

126.4 

69.52 

275.6 

620.6 

IIO4 

1723 

2482 

34°2 

44" 

400 

160 

128.0 

70.40 

279.0 

628.5 

III7 

1746 

25U 

3422 

4468 

410 

162 

129.6 

71.28 

282.5 

636.3 

H32 

1767 

2545 

3462 

4523 

420 
43° 

\66 

I3I.2 
132-8 

72.11 
73-04 

285.8 
289.5 

643-7 
652.0 

1  144 
1160 

1787 
1790 

22 

3505 
3539 

SB 

440 
45° 

168 
170 

134.4 
136.0 

73.92 
74.80 

293.0 
296-4 

659.9 
667.8 

"74 

1188 

1832 
1854 

2640 
2672 

3593 
3635 

4692 
4747 

408  GOLD  TABLE  AND   HYDRAULICS 

TABLE    FOR   WEIR    MEASUREMENT, 

GIVING  CUBIC  FEET  OF  WATER  PER  MINUTE  THAT  WILL 
FLOW  OVER  A  WEIR  I  INCH  WIDE  AND  FROM  ^  TO  2oJ 
INCHES  DEEP. 


Inches. 

M 

J4 

% 

^ 

% 

H 

% 

0 

.00 

.01 

.05 

.09 

.14 

.19 

.26 

•32 

I 

.40 

•47 

•  55 

.64 

•73 

.82 

.92 

1.02 

2 

1.  13 

1.23 

1-35 

1.46 

1.58 

1.70 

1.82 

1-95 

3 

2.07 

2.21 

2.34 

2.48 

2.61 

2.76 

2.90 

3-05 

4 

3.20 

3-35 

3.50 

3-66 

3.8i 

3.97 

4.14 

4.30 

5 

4-47 

4.64 

3.8i 

4.98 

5.15 

5.33 

5.5i 

5.69 

6 

5.87 

6.06 

6.25 

6.44 

6.62 

6.82 

7.01 

7.21 

7 

7.40 

7.60 

7.80 

8.01 

8.21 

8.42 

8.63 

8.83 

8 

9-05 

9.26 

9-47 

9.69 

9.91 

10.13 

10.35 

10-57 

9 

10.80 

II.  O2 

11.25 

11.48 

11.71 

11.94 

12.17 

12.41 

10 

12.64 

12.88 

13-12 

13.36 

13.60 

13.85 

14.09 

14-34 

ii 

14-59 

14.84 

15.09 

15-34 

15.59 

15-85 

l6.TI 

16.36 

12 

16.62 

16.88 

17.15 

17.41 

17.67 

17.94 

18.21 

18.47 

13 

18.74 

19.01 

19.29 

19.56 

19.84 

20.  II 

20.39 

2O.67 

14 

20.95 

21.23 

21.51 

21.80 

22.08 

22.37 

22.65 

22.94 

15 

23.23 

23.52 

23.82 

24.11 

24.40 

24.70 

25.00 

25.30 

16 

25.60 

25.90 

26.20 

26.50 

26.80 

27.11 

27.42 

27.72 

17 

28.03 

28.34 

28.65 

28.97 

29.28 

29.59 

29.91 

30.22 

18 

30.54 

30.86 

31.18 

31.50 

31.82 

32.15 

32.47 

32.80 

19 

33-12 

33-45 

33.78 

34-n 

34.44 

34.77 

35.10 

35.44 

20 

35-77 

36.11 

36.45 

36.78 

37.12 

37.46 

37.80 

38.15 

LOSS  OF  HEAD  IN  PIPE   BY  FRICTION 


409 


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412  GOLD  TABLE  AND   HYDRAULICS 


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INDEX 

PAGE 

Absorption  and  evaporation no,  153 

Acceleration  of  gravity 87 

Air  valves 187 

Alaska  mining       24 

Altar,  Mexico,  dry  placers 17 

Amalgam 67 

Amalgam  kettles 235 

Ancient  rivers 2,  9,  15 

Apex  law 336 

Area  of  circles 4°2 

of  sluices 85 

Asphalt  paint 175 

Assaying 25, 64 

Assessment  work 335,  342,  345 

Atlin,  B.  C 240,  256 

Attwood,  Melville,  Gold  Table 368 

Barr,  J.  A 247 

Batea 65 

Bazin  ditch  formula 98 

Bed-rock  sluices 75 

Black  sand 3*4 

Black  sand  experiments 322 

Black  sand  in  Caribou 267 

Black  sand,  platinum  in 9 

Blankets  in  sluices 71,  290 

Blasting  charge 243 

Blasting  dredging  ground 276 

Blasting  explosives .  242 

Blasting  gravel  banks     241 

413 


414  INDEX 

PAGE 

Booming 57 

Bowie,  Alex.  J.,  on  pipes 174 

on  riffles 140 

on  storage  reservoirs 153 

on  water  duty 228 

Bowman  reservoir 153 

Breckenridge,  Col 5,  150 

Brine  pumping 54 

Bucket  capacity 276 

Bucyrus 276 

chains 276 

construction 275 

dredge 270 

excavators 275 

Knight 260 

ladders 273 

speed 275 

Cabin  John,  Md 5 

Cable  towers 258 

Cableway 258 

Calculating  placer  ground 23 

California  Gulch,  Colo 5 

Caminette  Act      16,  206 

Cape  Nome,  Alaska     . 3 

Caribou  black  sands 267 

Centrifugal  pumps '.  247,  283,  294 

Chains,  bucket     276 

Chezy  formula 96,  98 

Claims,  recording 339,341 

size  of,  in  Canada 353 

size  of ,  in  U.  S 343,3^4 

Cleaning  bed  rock 233 

Clean-up 232 

Cliff  flumes 163 

Coefficient  of  pipe  entrance 381 

of  roughness 98 

Comstock  lode,  Nev 6 

Construction  of  hull 270 


INDEX  415 

PAGE 

Cost  of  dredges , 262 

of  dredging 269 

of  elevating      217,  202 

of  hydraulicking      298 

Coxe-Weisbach  formula,  pipes 181 

Cradle  or  rocker 66,  246 

Craig,  R.  R.,  stovepipe 174 

Crib  dams 156 

Culm  pile  mining 59 

Dams 155 

Dams,  debris 155 

Day,  Dr.,  black  sand  experiments 325 

Development  of  placer  mining 61 

Dipper  dredge 277 

power  for 308 

Disadvantages  of  buckets 277 

Ditches,  carrying  capacity 383 

depth  of  flow 203 

flow  of  water  in 194,  200 

form  for 196, 383 

safe  velocity  in 108,  194,  201,  207 

side  slope  for 201 

size  of 198 

table 388 

Ditch  lines 190 

surveys 190 

Dixon's  method  of  valuation     39 

Docoto's  method  of  valuation 36 

Dredges,  cost  of 269 

dipper 277 

power  for 293 

selection  of 265 

suction 282 

traction 297 

Dredging,  cost  of 268 

river  bars 264 

Drifting 42 

Drift  mining 237,  247 


416  INDEX 

PAGE 

Drift  removed  by  water 222,  228 

Dry  placers 7,  17 

Dry-placer  mining  machines 18,  297,  310 

Dubuat  formula,  ditches 207 

Dumping  ground      148 

Duty  of  elevators 219 

of  giants      224 

of  miner's  inch 225 

of  water 96 

Dynamite 242 

Edith  mine,  N.  C 250 

Edward  Edwards n 

Elevator,  Campbell's 221 

Ludlum's      221 

Elevators  at  Breckenridge,  Col 221 

at  Feather  River,  Cal 220 

cost  of  working 217,221 

duty  of 216 

hydraulic 214 

Empire  drill .    34,  45 

Estimating  placers 24,  28 

Evans  elevator 214 

Excavators  for  dredges 273 

Explosives 242 

Exploiting 227 

Eytelwein's  formula,  ditches 206 

Filling  pipes 190 

Flow  of  water  through  channels  (tables)      200,  387 

nozzles  (tables) 384 

orifices  (tables) 401 

pipes  (tables) 179,  374 

velocity  of 87 

Flume  construction     163 

carrying  capacity 163 

curves 167 

waste  gates 171 

Formulas:  Bazin,  on  ditches     98 


INDEX  417 

PAGE 

Formulas:  Chezy,  on  ditches 96 

on  pipes 116 

Coxe-Weisbach,  on  pipes 181 

Dubuat,  on  ditches 207 

Eytelwein,  on  ditches 206 

Francis,  on  weirs 172 

Kutter,  on  ditches 98 

Leslie,  on  ditches      96 

Poncelot,  on  ditches 206 

on  pipes 206 

Rankin,  on  pipes 182 

Smith,  on  pipes 172,  181,  206 

Weisbach,  on  pipes 181 

Free  miner's  certificate 349 

Fresno  power  plant     176 

Frictional  resistance 180 

in  ditches 167,  194 

Friction  in  pipe 125,  180 

pipe  bends 181 

sluices 167,  194 

Gantry 273 

Gates,  water     185 

Geology  of  placers i 

Georgia      246 

dredging 281 

Giant 210 

Giant,  spouting  velocity  of 211 

water  measurements  from 221 

Gilchrist,  A.  D 171 

Gold  and  talc 145 

float      58,  144 

flour 9,  137 

impurities  in 25 

leaf    . 9, 58 

movement  in  ditches      280 

nuggets 15 

saving  arrangements      252,  288 

table    .  368 


418  INDEX 

PAGE 

Golden  Feather  River     220 

Grade  for  ditches 206 

flumes  (table) 207 

sluices 194 

Graphical  hydraulics 98 

Ground  sluices      .    .    .    . 75 

Gulch  mining 7 

Hafer,  Claude 246 

Head,  loss  of  (table) 180,  409 

Head  of  water 179 

Heinrich,  O.  J 56 

Herschel,  Clemens 172 

Horse-power  calculations 122 

Horse-power  tables 372,  390 

Hoskins  giant 210 

Hull  construction 270 

Hungarian  riffles 147,  289 

Hutchins,  J.  P 181,  266 

Hydraulic  elevators 214 

mean  depth 86 

mining 50 

radius 86 

Hydraulicking,  cost  of 227 

water  for 228 

Ilmenite i 

Iron  ore  mining 56 

Keystone  drill  for  prospecting 44 

for  blasting 276 

Klamath  River  placers 16 

Klondike  placers 16 

laws     348 

mining     .    .   ' 244 

prospecting 349 

Knight  bucket 260 

Knuckle-joint 210 

Kutter,  on  ditches 98 


INDEX  419 

PAGE 

Land  patents 338 

Law  of  apex      335 

California  mine • 344 

Klondike 348 

Laying  pipe  . I75 

Le  Conte  on  water  transportation 83 

Lead  joints !y8 

Leslie's  formula,  ditches 0,5 

Lewis  and  Clark  exposition 325 

Leveling I9i; 

Lidgerwood  cableway      , .    .  < 258 

Lime  cartridges 52 

Lindgren  Waldmer 14 

Little  Creek,  Alaska 137 

Locating  claims 339 

Log  washers 250 

Long  Tom 71 

Lonridge,  C.  C 198 

Loss  of  head  in  pipes 128 

Lovett  concentrator 331 

Machinery  for  dredges 295 

Magalia,  Cal 248 

Magnetic  separation  of  black  sands 321,  332 

Magnetite i 

Marion  Company's  dredges 300 

Masonry  dams      156 

Mattison,  E.  E 174 

Measurements  of  gold  (table) 365,  369 

giants 225 

streams 162 

water 161 

water  by  color 172 

weirs  (table) 160,  403 

Mercury  in  sluices 238 

Mill  sites 347 

Mine  laws 333,345 

Mine  maps 222 

Miner's  head  day 225 


420  INDEX 

PAGE 

Miner's  inch 159 

duty  of 97,225 

(tables) 372 

Mining  by  booming 57 

coal  piles      59 

by  drifting 247 

by  fire Si,  245 

in  Alaska 244 

in  Georgia 246 

in  North  Carolina 249 

salt 53 

by  steam  points      245 

Mother  lode 5 

Neville,  Sir  John,  on  ditch  erosion 207 

North  Carolina 4,  249 

Nozzles 213 

Nozzles  (table)     390 

Nozzle  spouting  velocity 211 

Nozzle,  duty  of 224 

Nuggets 15 

Panning 62 

Pan  testing  of  placers 25,  28 

Packard,  G.  W 312 

Pay  dirt 4 

Perimeter 199 

Phillips,  J.  W 205 

Pipe,  areas  (table) 395,  402 

bends  (table)      183,  381,  385 

contraction  and  expansion 176 

corrosion 17, 132 

discharge 395 

Pipe  formula,  Chezy's 96,116 

Coxe-Weisbach 181 

Rankin's 182 

Smith's 172,  181,  206 

Pipe  friction     131, 180 

joints 176 


INDEX  421 

PAGE 
Pipe  laying I7S 

lines  and  ditches 135^  175 

loss  of  head  in 128,180,409 

painting 175,  183 

safe  head  for  riveted 404 

safe  working  pressure 394 

strength  of   .    . 182 

thickness 395 

tables 395 

weight  of 395 

Placer  calculations 22,  24 

claims 20,343 

cross-sections 23 

definition  of i,  n 

dry 7,i7 

geology  of      i 

investments 22, 137 

prospecting 7,19,227 

sampling 24 

testing  with  bore-holes 23 

drifts    .    .    .  '. 42 

pans 25 

Platinum  in  black  sands 267 

in  Caribou  sands 267 

Poncolot  formulas,  ditches  and  pipes 206 

Power  plant  for  dredges     293 

Pressure  box 176,  188 

Previous  staked  claims 20 

Prospecting  with  drills 22,  44 

Pump  for  tailing 293 

Quarrying      51 

Quicksilver  in  sluices 233 

Radford's  Factor     35 

Railroad  lands 337 

Rankin  on  pipe 182 

Raymond,  R.  W 33$ 

Recording  locations 34* 


422  INDEX 

PAGE 

Record  of  test  holes     .    .    .  . .  . .   .   .  35 

Reservoirs 153 

Retorting  mercury 235 

Revolving  screens 285 

Riffles,  block 141 

cast  iron 143 

charging 230 

Hungarian  ....... 147 

iron  rail 142 

pole ..    .    . 138 

slot 134 

stone 142 

Risdon  buckets 276 

River  claims      : 354 

dredging  laws,  Canada 362 

U.  S. 336 

Rivers,  ancient 14 

recent 14 

Riveted  steel  pipe 131 

Rockers 66 

Rubbing  surface 85 

Safe  velocity  in  ditches 108, 194,  201,  207 

Salt  mining 54 

Sampling  placers 25 

San  Juan  River,  Cal ...  . 2 

Screens,  rotating 285 

shaking 287 

Sea  beaches 3 

Selecting  a  dredge 265 

Self-contained  dredges 30 

Sellards,  E.  H 247 

Settling  dams 155 

Seward  Peninsula 4,  137 

Shaft  mines 239 

Shaft  testing 33 

Shaking  screens 287 

Sierra  Nevada  Mt.,  deposits 14 

Siphons 205 


INDEX  423 

PAGE 
Slot  riffles      139 

Sluice-box  area ' 75,  85 

calculations 84, 88 

construction .     70,  78 

depth 87 

dump 96 

grade 77,89 

length 76,80 

size  of      84 

Sluice,  stone  pavements      142 

charging  the 230 

mercury  in  the 230 

tunnels 205 

Smith,  Hamilton,  on  pipes 172,  181,  206 

Snake  River,  Idaho     72 

Spatterwork 54 

Spouting  velocity 211 

Spuds 295 

Square  root 402 

Stacker 292 

Stadia  chart 224 

Standpipe  valve 185 

Stanniferous  deposits n 

Steam  measurements 162 

Steam  point 245 

shovel  mining 256 

thawing 245 

Stewart,  C.  B 135 

Storage  reservoirs 153 

Storey,  W.  B 206 

Stovepipe  joint    ...    r 119 

Strength  of  pipe  .    .    .   ;   .   .  »-r  .  r% 182 

Suction  dredges 282 

Surface  rights 21 

Survey  of  ditch  line i53>  190 

Survey  of  progress 222 

Table  of  areas ; 402 

angular  resistance 382 


424  INDEX 

PAGE 

Table  of  circular  bend 385 

discharge  through  nozzles 390,  407 

discharge  through  orifices 40 

flow  through  channels 387 

flow  through  pipes 376 

giants 390,  402 

gold  values 369 

horse-power  from  nozzles 390 

horse-power  per  miner's  inch 372 

horse-power  per  cubic  foot 373 

loss  by  friction 409 

riveted  pipe 394 

safe  head  for 404 

weight  of  pipe 394 

weir  measurements 408 

Tailing  pump 293 

Tailing  stacker 292 

Telephone  lines 207 

Testing  placers 22 

with  drifts 42 

with  drills 31 

with  shaft 31 

Test  records 35 

Tinker,  E.  B 224 

Tin  deposits n 

Traction  dredges 297 

Transporting  power  of  water 80 

Traveling  tower 258 

Trestle  flumes 163 

Trinity  Co.,  Cal.,  placers 9 

Trough  washers 69 

Tumblers 295 

Tundra 3 

Tungsten 3 

Tunnel  mining 238 

Tunnels  in  ditch  lines      .    . 143 

Tunnel  sluicing 153 

Undercurrents  ,    ,   ,   ,   r 145 


INDEX  425 

PAGE 

Value  of  gravel  deposits      24,  29 

Valuing  dredging  ground 36 

Valves,  air 187 

water 185 

Velocity  of  flow 87 

table 407 

Virginia  gold  deposits 5 

Washing  gold  with  centrifugal  pumps 291 

Washing  gold  with  logs 250 

screens 285 

Water  area    . 371 

cartridge 52 

depth  in  ditches 108 

duty  of 97,  266 

for  hydraulicking 228,412 

friction 180 

gates 185, 189 

hammer 187 

loss 112 

measurements 162 

by  color .     171 

by  giants 224 

pressure 394 

rights 21,367 

supply 153 

transporting  power  of 80 

to  dirt  removed 97 

velocity  in  ditches 108,  194,  201,  207 

weight  of 371 

Waterfall  mining      58,226 

Weatherbee,  D'Arcy 294 

Weir  measurements 408 

Weisbach  on  pipes 181 

Well  drill  test  holes 33 

Wet  perimeter 85 

Wooden  stave  pipe 123 

Wood's  dry  placer  machine 311 

Wright,  P.,  on  gold  movement  in  ditches 280 

Yukon,  Canada 348 


